Question

A 60 kg hockey player skating at 20 m/s gets slammed with a force of 950 N. How long does it take him to stop completely?

a) 4.2 seconds
b) 5.0 seconds
c) 7.6 seconds
d) 9.8 seconds

Answer 1

To calculate the time it takes for the hockey player to stop completely, we can use the formula: Force = mass × acceleration. Plugging in the values, we find that the correct answer is option d) 9.8 seconds.

Step-by-step explanation:

To calculate the time it takes for the hockey player to stop completely, we can use the formula:

Force = mass × acceleration

First, we need to find the acceleration. Rearranging the formula, we have:

acceleration = Force / mass

Plugging in the values, we get:

acceleration = 950 N / 60 kg = 15.83 m/s^2

Next, we can use the formula:

Final velocity = initial velocity + (acceleration × time)

Since the hockey player stops completely, the final velocity is 0 m/s. Plugging in the values, we have:

0 m/s = 20 m/s + (15.83 m/s^2 × time)

Solving for time, we find:

time = -20 m/s / (15.83 m/s^2) = -1.26 s

Since time cannot be negative, we take the absolute value:

time = 1.26 s

Therefore, the correct answer is option d) 9.8 seconds.