An air track car with a mass of 0.75 kg and a velocity of 8.5 m/s to the right collides elastically with a 0.65kg car moving to the left with a velocity of 7.2m/s. If the collision is elastic, what is the speed and direction of each car after the collision?

Answers

Answer 1
Answer:

The final velocity of car 1 is -0.36 m/s to the left, and the final velocity of car 2 is 6.69 m/s to the right.

What is the conservation of momentum?

The conservation of momentum is a fundamental principle in physics that states that the total momentum of a closed system remains constant if no external forces act on the system. In other words, the total momentum of a system before a collision or interaction is equal to the total momentum of the system after the collision or interaction, as long as there are no external forces acting on the system.

Mathematically, we can express the conservation of momentum as follows:

P_initial = P_final

Where:

P_initial is the total momentum of the system before the interaction or collision

P_final is the total momentum of the system after the interaction or collision

Momentum is a vector quantity, which means it has both magnitude and direction. Therefore, the conservation of momentum applies separately in each direction. For example, if two objects collide and move in different directions after the collision, the momentum of one object in the positive direction will be equal and opposite to the momentum of the other object in the negative direction, so the total momentum of the system is conserved.

The conservation of momentum is an important principle in many areas of physics, such as mechanics, electromagnetism, and quantum mechanics. It is used to analyze collisions, explosions, rocket propulsion, and other physical phenomena involving the transfer of momentum.

Here in the Question,

To solve this problem, we can use the conservation of momentum and the conservation of kinetic energy, since the collision is elastic. According to these laws, the total momentum and total kinetic energy before and after the collision must be equal. We can write this as:

Total initial momentum = Total final momentum

and

Total initial kinetic energy = Total final kinetic energy

Let's first find the initial momentum of the system:

P_initial = m1v1 + m2v2

= (0.75 kg)(8.5 m/s) + (0.65 kg)(-7.2 m/s) (since car 2 is moving to the left, its velocity is negative)

= 1.225 kg m/s to the right

According to the law of conservation of momentum, the total momentum of the system must be conserved after the collision. Therefore, the final momentum must also be 1.225 kg m/s to the right.

Let's now find the initial and final kinetic energies of the system:

KE_initial = (1/2)m1v1^2 + (1/2)m2v2^2

= (1/2)(0.75 kg)(8.5 m/s)^2 + (1/2)(0.65 kg)(-7.2 m/s)^2

= 26.228 J

According to the law of conservation of kinetic energy, the total kinetic energy of the system must also be conserved after the collision. Therefore, the final kinetic energy must also be 26.228 J.

Let's now find the final velocities of the two cars. We can use the momentum conservation equation to set up a system of two equations (one for the conservation of momentum and one for the conservation of kinetic energy) with two unknowns (the final velocities of the two cars). Solving this system of equations, we get:

v1f = (m1-m2)/(m1+m2)v1 + 2m2/(m1+m2)v2

= (0.75 kg - 0.65 kg)/(0.75 kg + 0.65 kg)8.5 m/s + 20.65 kg/(0.75 kg + 0.65 kg)(-7.2 m/s)

= -0.36 m/s to the left

v2f = 2*m1/(m1+m2)*v1 - (m1-m2)/(m1+m2)v2

= 20.75 kg/(0.75 kg + 0.65 kg)8.5 m/s - (0.75 kg - 0.65 kg)/(0.75 kg + 0.65 kg)(-7.2 m/s)

= 6.69 m/s to the right

Therefore, the final velocity of car 1 is -0.36 m/s to the left, and the final velocity of car 2 is 6.69 m/s to the right.

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Answer 2
Answer: We can do this with the conservation of momentum. The fact it is elastic means no KE is lost so we don't have to worry about the loss due to sound energy etc.

Firstly, let's calculate the momentum of both objects using p=mv:

Object 1:
p = 0.75 x 8.5 = 6.375 kgm/s

Object 2 (we will make this one negative as it is travelling in the opposite direction):
p = 0.65 x -(7.2) = -4.68 kgm/s

Based on this we know that the momentum is going to be in the direction of object one, and will be 6.375-4.68=1.695 kgm/s

Substituting this into p=mv again:

1.695 = (0.75+0.65) x v
Note I assume here the objects stick together, it doesn't specify - it should!

1.695 = 1.4v
v=1.695/1.4 = 1.2 m/s to the right (to 2sf)

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Answers

dens = mass/volume. after crushing, vol less so density more. the actual density of the metal is the same, density of can changes

Final answer:

The density of a metal can, whether it is crushed or not, remains the same because density is an intrinsic property of matter, dependent only on the mass and volume of the substance. Changing the can's shape alters its volume but does not affect its mass or its density.

Explanation:

The density of a substance is the ratio of its mass to its volume (Density = Mass / Volume). This physical property is intrinsic to the substance, meaning it doesn't change regardless of the quantity or form the material is in.

When you crush a metal can, you're changing its shape and thereby altering its volume. However, the mass remains the same because you haven't removed or added any material. As a result, the density of the metal in the crushed can stays the same as the metal's density before the can was crushed.

Let's consider a practical example: a block of brass and a piece of rebar. Both have the same mass and are made of the same metal, but the block of brass has a larger volume. Nevertheless, the densities of these substances remain constant. That's because density is an intrinsic property, reflecting the compactness of material in a substance. Hence, even though you change the can's shape (thus, its volume), you have no impact on the metal's density.

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A dolphin swims 1.85 km/h. How far has the dolphin traveled after .60 h?

Answers

1.85 km every hour x 0.60 hours

1.85 x 0.6 = 1.11


The dolphin traveled 1.11 km.

What came before the big bang is one of the primary unanswered questions about the origin of _____.

Answers

Answer: The correct answer for the blank is- Origin of universe.

Big band theory is an explanation about the origin of universe ( that is how universe began or the birth of universe).

Big Bang theory states that all matter ( including past and present time) in the Universe have come into existence at the same time, that is approximately about  13.8 bya ( billion years ago).

At that particular time, all matter was in the form of very small ball ( that is a compact form) with infinite density and excess heat, which is known as a Singularity.

All of a sudden, the singularity started expanding, and the universe that we know today originated.

Answer:

Universe

Explanation:

Objects on the moon's surface have an acceleration due to gravity one-sixth that on the earth's. What would the 40 kg boy weigh on the moon? (Round answer to nearest tenth.)

Answers

acceleration is the same as the gravitational force. On earth that is 9.81 m/s^2. F=ma so if the acceleration is 1/6, then so if the force (weight). 40/6 N is your answer.

An electromagnetic am band radio wave could have a wavelength of?1) .005m
2) 5m
3) 500m
3) 5,000,000m

Answers

An electromagnetic am band radio wave could have a wavelength of 500m, i.e., 500 meters(Option 3).

What is wavelength?

A wavelength is a disturbance that travels into space with a given frequency and amplitude.

  • Electromagnetic wavelengths can be classified depending on their type of frequency.

In conclusion, an electromagnetic am band radio wave could have a wavelength of 500m (Option 3).

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The frequency of choice-3 is

         (3 x 10⁸ m/s) / (500 m)  =  600,000 Hz.

That number is the 600 near the bottom of the AM radio dial.

A small 20-kilogram canoe is floating downriver at a speed of 2 m/s. What is the canoe's kinetic energy?

Answers

Answer: 40 Joules

Explanation: Kinetic energy is the energy possessed by a body by virtue of its motion.

Kinetic energy depends on the mass and speed of the object.

K.E=(1)/(2)* mv^2

m= mass of canoe = 20 kg

v= speed of canoe = 2 m/s

K.E=(1)/(2)* 20kg* (2m/s)^2

K.E=40kgm^2s^-{2}=40Joules

(1kgm^2s^(-2)= 1Joule)

Ek=1/2mv^2 = (20)(1/2)(2x2) =40