Question

What average force is necessary to bring a 50.2-kg sled from rest to a speed of 2.8 m/s in a period of 20.1 s?

Answer 1

To solve this problem we will use the concepts related to the Impulse-Momentum Theorem for which it is specified as the product between force and change in time

$\Delta p = F\Delta t$

And

\Delta p = m\Delta v

Where,

$F = Force$

$\Delta t = \text{Change in Time}$

$\Delta v = \text{Change in velocity}$

$m = mass$

Rearranging to find the Force we have that

$F = \frac{\Delta p}{\Delta t}$

Using the expression between mass and velocity

$F = \frac{m(v_f-v_i)}{\Delta t}$

Our values are given as,

$m = 50.2kg\\v_i = 0m/s \\v_f = 2.8m/s \\\Delta t = 20.1s$

Then replacing we have that

$F = 6.99N$

Therefore the average force is 6.99N