Question No. 1 Marks = = 5 +5 +2 = 12

The driver of a 2.0 × 103 kg red car traveling on the highway at 45m/s slams on his brakes to avoid striking a second yellow car in front of him, which had come to rest because of blocking ahead as shown in above Fig. After the brakes are applied, a constant friction force of 7.5 × 103 N acts on the car. Ignore air resistance.
(a) Determine the least distance should the brakes be applied to avoid a collision with the other vehicle?
(b) If the distance between the vehicles is initially only 40.0 m, at what speed would the collision occur?
(c) Write your conclusive observations on the result obtained from this numerical. i.e. the importance of Physics in daily life.



Question No. 2 Marks = 8
Consider an automobile moving at v mph that skids d feet after its brakes lock. Calculate how far it would skid if it was moving at 2v and the brakes were locked.

As the coaster car rolls down the track from A to E, the potential energy values decrease and the kinetic energy value increase and the total mechanical energy values remain constant. The potential energy is greatest at point A and smallest at point E.  However, the kinetic energy is smallest at point A and largest at point E.

According the principle of conservation of mechanical energy, as the potential energy decreases, the kinetic energy increases.

[tex]P.E + K.E = M.A[/tex]

At point A, the coater has maximum potential energy.

At point E, the coaster has maximum kinetic energy.

We can fill the blanks as follows;

As the coaster car rolls down the track from A to E, the potential energy values decrease and the kinetic energy value increase and the total mechanical energy values remain constant.  The potential energy is greatest at point A and smallest at point E.  However, the kinetic energy is smallest at point A and largest at point E.

Based on the principle of conservation of mechanical energy, if the second simulation occurs at the same condition as the first, the height reached by coaster will be same.

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(a) The final velocity of the two vehicles if the collision was inelastic is 1.1 m/s.

(b)  For the elastic collision, the final velocity of the car is 9.81 m/s backwards and the final velocity of the truck is 2.19 m/s forward.

(c) The time taken to exert the given force is 0.00625 m (s).

The given parameters;

(a) The final velocity of the two vehicles if the collision was inelastic is calculated as follows;

[tex]m_1 u_1 + m_2u_2 = v(m_1+ m_2)\\\\12m + 10m(0) = v(m + 10m)\\\\12m = v(11m)\\\\v = \frac{12m}{11m} \\\\v = 1.1 \ m/s[/tex]

(b) The final velocity of the two vehicles if the collision was elastic is calculated as follows;

[tex]m_1 u_1 + m_2u_2 = m_1v_1 + m_2v_2\\\\\12m \ + \ 10m(0) = mv_1 + 10mv_2\\\\12m = m(v_1 + 10v_2)\\\\12 = v_1 + 10 v_2\ \ - --(1)[/tex]

Apply one-directional velocity equation:

[tex]u_1 +v_1 = u_2 + v_2\\\\12 + v_1 = 0 + v_2\\\\12+ v_1 = v_2 \ \ --- (2)[/tex]

Substitute the value of [tex]v_2[/tex] into equation (1);

[tex]12 = v_1 + 10(12 + v_1)\\\\12= v_1 + 120 + 10v_1\\\\12- 120 = 11v_1\\\\-108 = 11v_1\\\\v_1 = \frac{-108}{11} \\\\v_1 = -9.81 \ m/s\\\\[/tex]

Solve for [tex]v_2[/tex];

[tex]v_2 = 12 + v_1\\\\v_2 = 12 - 9.81\\\\v_2 = 2.19 \ m/s[/tex]

Thus, for the elastic collision, the final velocity of the car is 9.81 m/s backwards and the final velocity of the truck is 2.19 m/s forward.

(c)

The change in the momentum of the truck is calculated as;

[tex]\Delta P = m_2(v_2 - u_2)\\\\\Delta P = 10m(2.19)\\\\\Delta P = 21.9m[/tex]

The time taken to exert the given force is calculated as follows;

[tex]Ft = \Delta P\\\\t = \frac{\Delta P}{F} \\\\t = \frac{21.9 \ m}{3500} \\\\t = 0.00625 \ m (seconds)[/tex]

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Answer:

Explanation:

designer

illusionist

engineer

entrepreneur

salesperson

human

inventor

Answer:

A: P and N are both nonmetals, same strength: No

B: Most likely not

C: Same saying as B

D: Most likely yes

Explanation:

I don't actually know if i'm right, I just want to help you okay, so if it's wrong than sorry. Also I couldn't tell if the CI is a Ci(17) or CL(6+53)

Part reason why I was saying that B and C are most likely incorrect. And D the NH3 has more value than HF (if I remember)

As per the given situation, [tex]PH_3[/tex] is stronger acid than [tex]NH_3[/tex]. The correct option is A.

Any substance that tastes sour in water, turns blue litmus paper red, reacts with some metals to liberate hydrogen, reacts with bases to form salts, and promotes chemical reactions is considered an acid (acid catalysis).

Because strong acids have mostly ions in solution, the bonds that hold H and A together must be weak. Strong acids easily dissociate into ions.

Because weak acids exist primarily as molecules with only a few ions in solution, the bonds that hold H and A together must be strong.

[tex]PH_3[/tex] is a more potent acid than [tex]NH_3[/tex]. as PH3 has a pKa of -5.5 and [tex]NH_3[/tex] has a pKa of 9.9.

Thus, the correct option is A.

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Gases have heavier molecules. Since all gases have the same average kinetic energy at the same temperature, lighter molecules move faster and heavier molecules move slower on average.

Answer:

The one falling from the greatest height will have the greatest speed.

h = 1/2 g t^2        time for ball to fall distance h

h2 / h1 = t2^2 / t1^2       dividing equations

h2 / t2^2 = h1 / t1^2

Let v be the average speed (v2 = h2 / t2)

1 / t2 * v2 = 1 / t1 * v1

v2 / v1 = t2 / t1      the one taking the longest to fall has the greater av. speed

Check:

h4 / h1 = t4^2 / t1^2     or

t4 / t1 = (h4 / h1)^1/2

In this case t4 / t1 = (4 / 1)^1/2 = 2  or twice the average speed

t1 = (2 h / g)^1/2 = .2^1/2 = .447       using g = 10

t4 = (2 h / g)^1/2 = .8^1/2 = .894

v1 = 1 / .447 = 2.24 m/s average speed

v4 = 4 / .894 = 4.47    or twice the average speed

Answer:

hmmmmm ill get back later

Explanation:

Answer:

F

Explanation:

for every action there exists an equal and opposite reaction. The force acting on the two masses is identical in magnitude, but opposite in direction.

Answer:

Explanation:

v = u + at

Let Up be the positive direction

v(2) = 24 + (-9.8)(2) = 4.4 m/s   Positive result means Upward

v(3) = 24 + (-9.8)(3) = -5.4 m/s   Negative result means Downward

6.6 J/K

1.4 J/K

190 J/K

100 J/K

6.2 J/k

i think this is a answer

Water’s high specific heat capacity explain why water is liquid at room temperature

option C is the correct answer.

The specific heat capacity of an object is the amount of heat required to raise the temperature of a unit mass of the substance by 1 kelvin.

The relationship between specific heat capacity and heat capacity of a substance is given as;

c = Q/mΔθ

where;

A high specific heat capacity implies that the substance absorbs more energy to change its state.

Thus, water has a high specific heat, meaning it takes more energy to increase the temperature of water compared to other substances. When water absorb more heat energy, it changes its state.

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Answer:

The temperature is constant at 'X'. No increase or decrease. Would be same answer if there were a 'X' at temperature 'D'.

Slope of graph is zero so no change in the temperature.

Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.

Given graph of temperature and time, at position x there in no change in temperature with time so temperature is not changing.

Slope of graph is zero so no change in the temperature.

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A child on ice skates is given a small push from behind by a parent. There is an unbalanced force on the child, and the child’s motion will change direction or increase speed.

A child on ice skates is given a small push from behind by a parent. How are forces used to describe the resulting motion?

A child on ice skates is given a small push from behind by a parent. There is an unbalanced force on the child, and the child’s motion will change direction or increase speed.

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Answer:

40m/s

Explanation:

V= u + at

v= 0

a= -10

t= 4

0= u -40

u= 40m/s

just trial!!!!!!!

Answer:

[tex] \huge \bold \blue{ \underline{ answer}}[/tex]

The splitting up of light into its constituent colours while passing from one medium to the other is called dispersion.

The magnitude and direction of the velocity of the  golf ball is 6.4 m/s at 38.7⁰.

The given parameters:

The magnitude of the resultant velocity of the golf ball is calculated as follows;

[tex]v= \sqrt{v_y^2 + v_x^2} \\\\v = \sqrt{4^2 + 5^2} \\\\v = 6.4 \ m/s[/tex]

The direction of the golf ball's velocity is calculated as follows;

[tex]\theta = tan^{-1} (\frac{v_y}{v_x} )\\\\\theta = tan^{-1}(\frac{4}{5} )\\\\\theta = 38.7 \ ^0[/tex]

Thus, the magnitude and direction of the velocity of the  golf ball is 6.4 m/s at 38.7⁰.

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Answer:

A student removed a wool hat from her head. Her hair stood up from static electricity. What did her hat do to cause this? ... Yes, the motor would run faster because the increased electrical force increases the magnetic force in the motor.

A student removed the wool from her head due to the static charge of electricity, it is caused.

A difference in electric charge within, on the surface of, or between two materials results in static electricity. Until it can be expelled through an electrical discharge or current, the charge stays. In contrast to current electricity, which transmits energy by letting an electric charge flow through a conductor or a space, static electricity does not transport energy.

When two surfaces come into contact, wear, and separate from one another when at least a single surfaces has a good resistance to electric current, a static electrostatic attraction can be produced. Because individuals can feel, hear, and even see a spark when the extra charge is neutralized when placed close to a powerful electrical conductor, most people are familiar with static electricity's effects.

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Answer:

The forces are balanced on both animals because they are not moving

More importantly than not moving is not accelerating.

Explanation:

Answer: A! the animals are doing the same thing, the force is applied to both also there not moving

Explanation:

0.8 seconds

Explanation:

time of flight = 2u/g

u=4m/s

g=10

= 8/10

= 0.8 sec

just a trial...not sure!!!

Given :

∅ = 60⁰

u = 4 m/s

g = 10m/s²

to find :

T = ?

Solution :

as per formula,

[tex]t = \frac{2u \: sin \theta}{g} [/tex]

now put the value : [tex]t \: = \frac{2 \times 4 \times sin \: 60}{10} [/tex]

as we know [tex] sin60 \: = \frac{ \sqrt{3} }{2} [/tex]

therefore,

[tex]t \: = \frac{8 \times \frac{ \sqrt{3} }{2} }{10} [/tex]

as we solve this we get,

[tex]t \: = \frac{ 2\sqrt{3} }{5} [/tex]

that's t = 0.69 sec

[tex]\sf\fbox\red{\:I \:hope \:it's \:helpful \:to \:you}[/tex]

Answer:

If you mean by temperature

Water, cause say the water just sits there, it'll take a few minutes to cool down. But for concrete having all the hot sun rays on it during summer, can make it very hot, if you put 'cold water' there, it'll only last there for a moments (and that's by effect not waiting), if you wait for it to cooldown by itself, it'll take quite awhile.

If you mean solidify:

The stuff required to make concretes takes HOURS and HOURS to finish solidifying, unlike water being turn into ice normally only takes about half an hour or an hour (maybe 2) in the freezer (I don't know how long for ice, but not long at all in comparison to concrete).

Explanation:

Explanation was mostly part of the answer

Answer:

D  Is true - the velocities (and squared) follow the appropriate statistical curve

The molecules have a range of kinetic energies at a certain temperature.  As the temperature increases, their kinetic energy and molecular speed increases.

Kinetic theory of gases describes the nature of ideal gases and their volume, pressure and kinetic energy. As per this theory the gases are made of tiny particles which have negligible mass compared to that of the container.

Kinetic theory states that the kinetic energy of all gases increases with increase in temperature which is independent of the masses and and at certain temperature all the gases are having same range of kinetic energies.

The velocity of all the gaseous particles increases with increasing in temperature which results in the increase in kinetic energy. Hence, option D is correct.

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What metal is not at room temperature?

Mercury is a metallic chemical element that is an only metal that is not a solid at room temperature.

Answer:

Cool. What’s the Question?

Explanation:

Answer:

[tex]47 \ \frac{m}{s}[/tex]

Explanation:

s = displacement (m)

u = initial velocity [tex](\frac{m}{s})[/tex]

v = final velocity [tex](\frac{m}{s})[/tex]

a = acceleration [tex](\frac{m}{s^{2} })[/tex]

t = time (s)

s = 235

a = -4.7

v = 0

v² = u² + 2as

(0)² = u² + 2(-4.7)(235)

u² - 2209 = 0

u² = 2209

u = 47

Answer:

[tex]\boxed {\boxed {\sf 47 \ m/s}}[/tex]

Explanation:

We are asked to find the initial velocity of the car before it began to accelerate.

We are given the acceleration, distance, and final velocity, so we will use the following kinematic equation:

[tex]{v_f}^2 = {v_i}^2 + 2ad[/tex]

The car's acceleration is -4.7 meters per second square. It traveled a distance of 235 meters. It came to rest, or a final velocity of 0 meters per second.

Substitute the values into the formula.

[tex](0 \ m/s)^2 = {v_i}^2 + 2 (-4.7 \ m/s^2)(235 \ m)[/tex]

[tex]0 = {v_i}^2 + 2 (-4.7 \ m/s^2)(235 \ m)[/tex]

Multiply the numbers in parentheses.

[tex]0= {v_i}^2 + (-2209 \ m^2 / s^2)[/tex]

Add -2209 to both sides of the equation.

[tex]0+ 2209 \ m^2 /s^2 = {v_i}^2+ ( -2209 \ m^2 /s^2 )+ 2209 \ m^2 /s^2[/tex]

[tex]2209 \ m^2 /s^2 = {v_i}^2[/tex]

Take the square root of both sides.

[tex]\sqrt {2209 \ m^2 /s^2} = \sqrt {{v_i}^2[/tex]

[tex]\sqrt {2209 \ m^2 /s^2} = v_i[/tex]

[tex]47 \ m/s = v_i[/tex]

The inital velocity of the car was 47 meters per second.

The statement that describes the motion of a block while it is in equilibrium is: The block moves at a constant speed.

A state of equilibrium in physics refers to a state of rest or the forces exerted on the object is in a balanced state.

In dynamic equilibrium, the acceleration of a body is zero. This means that the body is moving at a uniform speed.

Therefore, the statement that describes the motion of a block while it is in equilibrium is: The block moves at a constant speed.

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Answer:

Looks good to me

Explanation:

#2 should probably be turning potential energy to kinetic.

Answer:

Force is equal to the change in momentum per change in time.

Explanation:

That situation is described by Newton's Second Law of Motion. According to NASA, this law states, "Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration." This is written in mathematical form as Force = mass.

The quantity of heat (Q) that is required to increase the temperature at constant volume is 18,082.95 Joules.

Given the following data:

Scientific data:

To determine the quantity of heat (Q) that is required to increase the temperature at constant volume:

First of all, we would find the number of moles of oxygen gas.

[tex]Number\;of\;moles = \frac{mass}{molar\;mass}\\\\Number\;of\;moles = \frac{192}{32}[/tex]

Number of moles = 6 moles.

At constant volume, the heat capacity for a diatomic gas is given by:

[tex]C_v = \frac{5}{2} R\\\\C_v =\frac{5}{2} \times 8.314[/tex]

Heat capacity = 20.785 J/molK.

At constant volume, the quantity of heat (Q) is given by this formula:

[tex]Q = nC_v \Delta T\\\\Q=6 \times 20.785 \times 145[/tex]

Quantity of heat (Q) = 18,082.95 Joules

Note: [tex]\Delta T[/tex] = 145°C = 145 K (since the difference is the same).

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Answer:B

Explanation:

Answer: b

Explanation: b as it slows down and decelerates