A hockey puck has a mass of 0.120 kg and is at rest. A hockey player makes a shot, exerting a constant force of 29.5 N on the puck for 0.16 s. With what speed does it head toward the goal?
To find the speed of the puck heading toward the goal, we can use the equation: v = F*t/m
Where:
v = speed of the puck
F = force applied on the puck
t = time for which the force is applied
m = mass of the puck
Given:
m = 0.120 kg
F = 29.5 N
t = 0.16 s
Substituting the given values into the equation, we have:
v = (29.5 N * 0.16 s) / 0.120 kg
Simplifying the expression:
v = 4.72 m/s
Therefore, the puck heads toward the goal with a speed of 4.72 m/s.
To find the speed of the hockey puck after the shot, we can use the equation:
Force * time = change in momentum
Since the hockey puck starts from rest, the initial momentum is zero. So we can rewrite the equation as:
Force * time = mass * final velocity
Rearranging the equation to solve for final velocity:
Final velocity = (Force * time) / mass
Plugging in the given values:
Force = 29.5 N
Time = 0.16 s
Mass = 0.120 kg
Final velocity = (29.5 N * 0.16 s) / 0.120 kg
Calculating the final velocity:
Final velocity = 39.066666... m/s
Therefore, the hockey puck heads towards the goal with a speed of approximately 39.07 m/s.
You should have come across a law that says the momentum change equals the impulse. In your case, the momentum change is the final momentum.
M*V = F*t
Plug in the appropriate numbers and solve for V