A hockey puck is hit on a frozen lake and starts moving with a speed of 13.60 m/s. Exactly 6.2 s later, its speed is 7.20 m/s. (a) What is the puck's average acceleration?

-1.03 m/s²

Explanation:

Acceleration: This can be defined as the rate of change of velocity. The S. I unit of acceleration is m/s².

Mathematically, acceleration is expressed as

a = (v-u) / t ... Equation 1

Where a = acceleration, v = final velocity, u = initial velocity, t = time.

Given: u = 13.60 m/s, v = 7.20 m/s t = 6.2 s.

Substituting into equation 2

a = (7.20-13.60) / 6.2

a = - 6.4/6.2

a = - 1.03 m/s²

Note: a is negative because, the hockey puck is decelerating.

Hence the average acceleration = - 1.03 m/s²