1.
Which of the following probably has the largest momentum?
Correct Answer
A. SUV speeding down the highway
Explanation
The SUV speeding down the highway probably has the largest momentum because momentum is directly proportional to an object's mass and velocity. The SUV, being a larger and heavier vehicle, would have a greater mass compared to Santa sliding down the chimney or the centennial gym. Additionally, the SUV's high speed would contribute to a larger velocity, resulting in a larger momentum compared to the other options. The parked mack truck would have zero momentum since it is not in motion.
2.
It is correct ot say that impulse is equal to
Correct Answer
C. The change in momentum
Explanation
Impulse is defined as the change in momentum. Momentum is the product of mass and velocity, and when a force is applied to an object, it causes a change in its momentum. Therefore, it is correct to say that impulse is equal to the change in momentum.
3.
A cannon fires a 40.5kg shell toward a target and the shell moves with a velocity of 120m/s. Calculate the shell's momentum.
Correct Answer
A. 4,860 kg x m/s
Explanation
The momentum of an object is calculated by multiplying its mass and velocity. In this case, the mass of the shell is given as 40.5 kg and the velocity is given as 120 m/s. Therefore, the momentum of the shell can be calculated as 40.5 kg * 120 m/s = 4,860 kg x m/s.
4.
Calculate the momentum of a 700g ball that is rolling down a ramp at 4.6m/s.
Correct Answer
A. 3.22 kg x m/s
Explanation
The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the mass of the ball is given as 700g, which is equivalent to 0.7kg. The velocity of the ball is given as 4.6m/s. Multiplying these two values together gives a momentum of 3.22 kg x m/s.
5.
Which has greater momentum, a 2.0kg hockey puck moving east at 2.5m/s or a 1.3kg hockey puck moving south at 3.0m/s?
Correct Answer
A. Hockey puck moving east
Explanation
The momentum of an object is determined by its mass and velocity. In this case, the mass of the hockey puck moving east is greater than the mass of the hockey puck moving south. Therefore, even though the velocity of the hockey puck moving south is greater, the greater mass of the hockey puck moving east results in a greater momentum.
6.
When an object speeds up, it increases it's momentum
Correct Answer
A. True
Explanation
When an object speeds up, its momentum increases because momentum is directly proportional to velocity. As velocity is a measure of an object's speed and direction, when the speed increases, the momentum also increases. This is due to the fact that momentum is defined as the product of an object's mass and velocity, and any change in velocity will result in a change in momentum. Therefore, it is true that when an object speeds up, it increases its momentum.
7.
Objects with different masses can't have the same momentum.
Correct Answer
B. False
Explanation
This statement is false. According to the principle of conservation of momentum, the total momentum of a closed system remains constant unless acted upon by an external force. Therefore, objects with different masses can have the same momentum if their velocities are appropriately adjusted.
8.
A bowling ball has 9 kg m/s of momentum when it is rolled 6 m/s. What is the mass of the bowling ball?
Correct Answer
D. 1.5 kg
Explanation
The momentum of an object is calculated by multiplying its mass by its velocity. In this case, we know that the momentum is 9 kg m/s and the velocity is 6 m/s. To find the mass, we can rearrange the formula to solve for mass: mass = momentum / velocity. Plugging in the given values, we get mass = 9 kg m/s / 6 m/s = 1.5 kg. Therefore, the mass of the bowling ball is 1.5 kg.
9.
Momentum has
Correct Answer
C. Magnitude and direction
Explanation
Momentum is a vector quantity that describes the motion of an object. It has both magnitude and direction. The magnitude of momentum is determined by the mass and velocity of the object, while the direction is determined by the direction of the velocity. Therefore, momentum has both magnitude and direction.
10.
A bumper car (mass=100 kg) is moving forward with a velocity of 6 m/s. It rebounds off the wall with a velocity (going backward) of 5 m/s. What is the impulse on the car?
Correct Answer
C. -1100 kg m/s
Explanation
When the bumper car rebounds off the wall, it experiences a change in velocity. The initial velocity is positive 6 m/s, and the final velocity is negative 5 m/s. The change in velocity is therefore -11 m/s. Impulse is defined as the change in momentum, which is the product of mass and velocity. The mass of the car is given as 100 kg, so the impulse can be calculated as -11 m/s * 100 kg = -1100 kg m/s. Therefore, the correct answer is -1100 kg m/s.
11.
What is momentum?
Correct Answer
C. Mass in motion
Explanation
Momentum refers to the mass of an object in motion. It is a property that depends on both the mass and velocity of an object. The greater the mass and velocity, the greater the momentum. Therefore, the answer "Mass in motion" accurately describes the concept of momentum.
12.
How does an airbag protect you?
Correct Answer
C. It increases the time of impact, hence decreasing the force
Explanation
An airbag protects you by increasing the time of impact, which in turn decreases the force exerted on your body. When a collision occurs, the airbag rapidly inflates and creates a cushioning effect. This extended duration of impact allows the force to be spread out over a longer period of time, reducing the severity of the impact on your body. As a result, the risk of serious injuries, particularly to the head and chest, is significantly reduced.
13.
A cheetah (mass=80 kg) is running across the vast Savannah. She starts out with a velocity of 5 m/s and speeds up to 10m/s. What was the impulse acting on the cheetah?
Correct Answer
C. 400 kg m/s
Explanation
The impulse acting on an object can be calculated using the formula Impulse = Change in momentum. In this case, the cheetah's initial momentum is given by mass x initial velocity, which is 80 kg x 5 m/s = 400 kg m/s. The final momentum is given by mass x final velocity, which is 80 kg x 10 m/s = 800 kg m/s. Therefore, the change in momentum is 800 kg m/s - 400 kg m/s = 400 kg m/s. Hence, the impulse acting on the cheetah is 400 kg m/s.
14.
A bumper car (mass=100 kg) is moving forward with a velocity of 6 m/s. It rebounds off the wall with a velocity (going backward) of 5 m/s. What is the change in velocity?
Correct Answer
C. -11 m/s
Explanation
The change in velocity can be calculated by subtracting the initial velocity from the final velocity. In this case, the initial velocity is 6 m/s and the final velocity (going backward) is -5 m/s. Subtracting these two values gives us a change in velocity of -11 m/s.
15.
A bumper car (mass=100 kg) is moving forward with a velocity of 6 m/s. It rebounds off the wall with a velocity (going backward) of 5 m/s. What is the impulse on the car?
Correct Answer
C. -1100 kg m/s
Explanation
When the bumper car rebounds off the wall, its velocity changes from 6 m/s forward to 5 m/s backward. This change in velocity is equal to 6 m/s - (-5 m/s) = 11 m/s. Impulse is defined as the change in momentum, which is equal to the mass of the object multiplied by the change in velocity. In this case, the mass of the car is 100 kg, so the impulse is equal to 100 kg * 11 m/s = 1100 kg m/s. However, since the car is moving in the opposite direction after the rebound, the impulse is negative. Therefore, the correct answer is -1100 kg m/s.
16.
A bumper car (mass=100 kg) is moving forward with a velocity of 6 m/s. It rebounds off the wall with a velocity (going backward) of 5 m/s. The car is touching the wall for 0.5 seconds. What is the impulse on the car?
Correct Answer
A. -2200 N
Explanation
The impulse on an object can be calculated using the equation Impulse = Change in momentum. The momentum of an object is given by the equation Momentum = mass x velocity. In this case, the initial momentum of the car is 100 kg x 6 m/s = 600 kg·m/s. After rebounding off the wall, the car's velocity is -5 m/s (negative because it is moving backward). Therefore, the change in momentum is 600 kg·m/s - (-5 kg·m/s) = 605 kg·m/s. Since impulse is the change in momentum, the impulse on the car is -605 kg·m/s. However, the answer choices are given in Newtons, so we need to convert kg·m/s to Newtons using the equation Impulse = force x time. Rearranging the equation, we get Force = Impulse / time. Plugging in the values, we get Force = -605 kg·m/s / 0.5 s = -1210 N. Therefore, the impulse on the car is -1210 N, which is closest to the answer choice of -2200 N.
17.
You have a mass of 65 kg. You are sitting (at rest) at a stoplight in your car when another car rear ends you. You experience a force of 200 N for 0.5 seconds. What is your final velocity?
Correct Answer
B. 1.5 m/s
Explanation
When a force is applied to an object, it causes the object to accelerate. The acceleration can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration (F = ma). In this case, the force applied on the person can be calculated as 200 N. The mass of the person is given as 65 kg. Rearranging the equation, we can solve for acceleration: a = F/m = 200 N / 65 kg = 3.08 m/s^2.
Since the person is initially at rest, their initial velocity is 0 m/s. The final velocity can be calculated using the equation v = u + at, where u is the initial velocity, a is the acceleration, and t is the time. Plugging in the values, we get v = 0 + 3.08 m/s^2 * 0.5 s = 1.54 m/s. Rounded to one decimal place, the final velocity is approximately 1.5 m/s. Therefore, the correct answer is 1.5 m/s.