If the 60-kg player is running forward at 7.0m/s when she makes contact with the dummy, what is the players velocity at the end of the 1.20s impact?
To calculate the player's velocity at the end of the impact, we can use the principle of conservation of momentum. According to this principle, the momentum before the impact is equal to the momentum after the impact.
The momentum (p) of an object is given by the formula:
p = mass * velocity
Before the impact, the player's momentum can be calculated by multiplying the mass (60 kg) with the initial velocity (7.0 m/s):
Momentum before = 60 kg * 7.0 m/s
During the impact, the player experiences a change in momentum. This change in momentum is caused by the force applied by the dummy. The force is given by Newton's second law of motion:
Force (F) = mass * acceleration
The acceleration during the impact can be calculated using the formula:
acceleration = (change in velocity) / time
Since the time of the impact (t) is given as 1.20 seconds, and the final velocity (v) is what we want to calculate, the change in velocity can be expressed as:
(change in velocity) = v - 7.0 m/s
Now, we can calculate the acceleration during the impact:
acceleration = (v - 7.0 m/s) / 1.20 s
Using Newton's second law, we can write the equation for the force during the impact:
Force = mass * acceleration
The force during the impact is the same as the force applied by the dummy on the player during the impact.
Now, let's use the principle of conservation of momentum to find the final velocity. Since momentum before = momentum after, we have:
Momentum before = Momentum after
Therefore:
mass * initial velocity = mass * final velocity
Now, we can set up the equation using the given values:
60 kg * 7.0 m/s = 60 kg * final velocity
Solving this equation for the final velocity, we get:
final velocity = (60 kg * 7.0 m/s) / 60 kg
Simplifying this, we find:
final velocity = 7.0 m/s
Therefore, the player's velocity at the end of the 1.20 s impact is 7.0 m/s.