Will you check my work and help me with the last two problems please?
A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?
-(12 kg/m/s) / 4kg=3m/s
A ball is moving at 4 m/s and has a momentum of 48 kg m/s. What is the ball's mass?
-(48kg/m/s) / (4m/s) =12 kg
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of? (This one I don't know how to work)
A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is? (This one I don't know how to work)
Your first two answers look OK.
3rd question:
Assuming that all momentum is conserved, the total momentum after the collision is the same as before the collision. The bowling ball is at rest, so no momentum there. The putty has a momentum of 1kg * 1m/s=1kg*m/s. After the collision, the putty and the bowling ball are stuck together for a total mass of 6kg and have the same total momentum that the putty alone had before the collision. While not asked, the velocity after the collision is 1/6 m/s.
4th question:
Force = dp/dt where p is the momentum.
dp= 1000kg * 10m/s
dt= 5s
To find the momentum of the combined system after the collision between the putty and the bowling ball, we need to apply the law of conservation of momentum. According to this law, the total momentum before the collision is equal to the total momentum after the collision.
Before the collision, the putty has a momentum of (mass of the putty) x (velocity of the putty) = (1 kg)(1 m/s) = 1 kg m/s.
The bowling ball is initially at rest, so its momentum is zero.
After the collision, the putty and the bowling ball stick together and move as one object. Let's assume their combined mass is M kg, and their combined velocity is v m/s.
The total momentum after the collision is given by (combined mass) x (combined velocity) = Mv.
Since the total momentum before the collision is equal to the total momentum after the collision, we can set up the equation:
Total momentum before collision = Total momentum after collision
1 kg m/s + 0 kg m/s = Mv
1 kg m/s = Mv
To find the value of Mv, we need more information. Are there any additional details provided in the problem?
Regarding the second problem, to find the average braking force experienced by the car, we can use Newton's second law, which states that force is equal to the rate of change of momentum. The change in momentum of the car during braking can be calculated using the equation:
Change in momentum = (final momentum) - (initial momentum)
The final momentum of the car is 0 kg m/s, as it comes to a stop. The initial momentum can be calculated as:
Initial momentum = (mass of the car) x (initial velocity of the car) = (1000 kg)(10 m/s) = 10,000 kg m/s.
Therefore, the change in momentum is 0 kg m/s - 10,000 kg m/s = -10,000 kg m/s (since the car is slowing down).
To calculate the average braking force, we need to divide the change in momentum by the time taken for the car to come to a stop. The time is given as 5 s.
Average braking force = (change in momentum) / (time)
= (-10,000 kg m/s) / (5 s)
= -2000 N (note the negative sign indicates that the force is acting against the direction of motion)
So, the average braking force experienced by the car is -2000 N.