1.
The momentum of a body is equal to its mass multiplied by its velocity.
Correct Answer
A. True
Explanation
The statement is true because momentum is defined as the product of an object's mass and its velocity. In other words, the momentum of a body is directly proportional to both its mass and its velocity. This relationship is described by the equation p = mv, where p represents momentum, m represents mass, and v represents velocity. Therefore, the statement accurately states that the momentum of a body is equal to its mass multiplied by its velocity.
2.
A ball of mass 3kg is moving to the right with velocity 3m/s and a ball of mass 1kg is moving to the left with velocity 2m/s. we can use the principle of conservation of mass to determine the velocity of the other ball after the collision.
Correct Answer
B. False
Explanation
The principle of conservation of mass does not apply to determine the velocity of the other ball after the collision. The principle of conservation of momentum, on the other hand, can be used to determine the velocity of the other ball after the collision.
3.
What is true about impulse and momentum
Correct Answer
C. Momentum is the mass of a substance multiplied by the velocity while impulse is just the change of momentum
Explanation
Momentum is defined as the product of an object's mass and its velocity. It represents the quantity of motion possessed by an object. On the other hand, impulse is the change in momentum of an object. It is equal to the force applied to an object multiplied by the time interval over which the force acts. Therefore, the correct answer states that momentum is the product of mass and velocity, while impulse is the change in momentum.
4.
A 71.25 kilogram motorcycle is moving at a speed of 33.75 m/s. What is the momentum of the cycle?
Correct Answer
B. Greater than 200 kg m/s
Explanation
The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the mass of the motorcycle is given as 71.25 kilograms and its velocity is given as 33.75 m/s. When these values are multiplied together, the result is 2401.875 kg m/s, which is greater than 200 kg m/s. Therefore, the momentum of the motorcycle is greater than 200 kg m/s.
5.
A small car (mass = 71.25 kilograms), moving at 52.5 m/s, crashes head on with a 285 kilogram truck moving at 33.75 m/s in the opposite direction (negative velocity). If the two cars become intertwined and mangled (inelastic), with what velocity does the wreckage move? (Don't forget direction!)
Correct Answer
D. A magnitude greater than 30 m/s moving in the initial direction of the truck
Explanation
When the small car and the truck collide, they become intertwined and mangled, forming a single mass. According to the law of conservation of momentum, the total momentum before the collision is equal to the total momentum after the collision. Since the truck has a greater mass and a higher initial velocity, it contributes more to the total momentum. Therefore, the wreckage will move with a magnitude greater than 30 m/s in the initial direction of the truck.
6.
Because of the principle of conservation of momentum, a rocket can get rid of its empty stages
Correct Answer
D. To increase velocity
Explanation
According to the principle of conservation of momentum, the total momentum of a system remains constant unless acted upon by an external force. In the case of a rocket, when it gets rid of its empty stages, it reduces its total mass. As momentum is the product of mass and velocity, by decreasing the mass, the rocket can increase its velocity to maintain the same momentum. Therefore, the correct answer is "to increase velocity".
7.
A 50 kg skateboarder is riding his 2.3 kg skateboard at a speed of 4 m/s.What is his momentum?
Correct Answer
A. Greater than 200 kg m/s
Explanation
The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the skateboarder has a mass of 50 kg and is riding a skateboard with a mass of 2.3 kg at a speed of 4 m/s. Therefore, the momentum can be calculated as follows: momentum = (mass of skateboarder + mass of skateboard) x velocity = (50 kg + 2.3 kg) x 4 m/s = 52.3 kg x 4 m/s = 209.2 kg m/s. Since the calculated momentum is 209.2 kg m/s, which is greater than 200 kg m/s, the correct answer is "greater than 200 kg m/s".
8.
A 0.2 kg red cue ball rolling at 1.4 m/s elastically collides directly with a 0.2 kg 9-Ball at rest.Which of the following is true?
Correct Answer
D. The red cue ball would have a velocity of 0 m/s
Explanation
When two objects collide elastically, the total momentum before the collision is equal to the total momentum after the collision. In this case, the red cue ball is rolling at 1.4 m/s and collides elastically with the stationary 9-Ball. Since the 9-Ball is at rest, its initial velocity is 0 m/s. After the collision, the red cue ball will transfer all of its momentum to the 9-Ball, causing it to move in the opposite direction. Therefore, the red cue ball will come to a stop and have a velocity of 0 m/s.
9.
In a perfectly elastic collision, a ball dropped from a certain height would bounce
Correct Answer
B. At the same height
Explanation
In a perfectly elastic collision, the kinetic energy is conserved. When a ball is dropped from a certain height and it undergoes a perfectly elastic collision with the floor, it will bounce back with the same amount of kinetic energy it had before the collision. This means that it will reach the same height as the initial drop, as the gravitational potential energy is converted back into kinetic energy during the bounce. Therefore, the ball will bounce at the same height.
10.
In a perfectly inelastic collision, a ball dropped from a certain height would bounce
Correct Answer
D. Would stick to the floor
Explanation
In a perfectly inelastic collision, the objects involved stick together and move as one mass after the collision. This means that the ball would stick to the floor and not bounce back up to any height.