Emily W. answered • 12/01/22
B.S. in Physics with 7+ years Experience
I am not sure what the question is, but I am going to solve for the impulse because that’s what I think they would ask.
given:
vi = -5 m/s (downward)
vf after rebound = +2.5 m/s (upward is positive)
m = 0.61 kg
Impulse is represented by J and has 3 different equations that are all interchangeable:
J = change in momentum
J = m * change in velocity
J = Force * time in contact
We can choose the equation that fits our givens best. That would be equation 2.
J = ?
m = 0.61 kg
change in v = vf - vi = 2.5 - - 5 = +7.5 m/s
plug into equation
J = (0.61)(7.5) = 4.575 kgm/s (upward)
If impulse is not what you’re looking for please let me know thanks!
Emily W.
Awesome! To find the average force, we are looking back at our J equations and this time choosing the equation that is J = Force * time in contact. **IMPORTANT** This equation will give us the force of the floor on the ball, not the force of the ball on the floor. To get the force of the ball on the floor, we will simply reverse the sign of the answer at the end. This time we know J = 4.575 kgm/s and we are given time in contact = 0.04 seconds so we can plug in to find force. 4.575= Force * 0.04 Divide by 0.04 on both sides: Force = 4.575/0.04 = 114.375N Force of floor on ball is 114.375N directed upward. This means force of ball on floor is -114.375N directed downward.12/01/22
Jazmin M.
The impulse was exactly what I was looking for! that and: If the ball is in contact with the floor for 0.04 s, what is the average force of the ball on the floor (in N) Thank you for your help!12/01/22