Question

A delinquent is able to accelerate a 200 g snowball from rest to a speed of 20 m/s over a distance of 1.2 m. What is the work (in J) done on the ball by this troubled youth? You may assume that the snowball travels perfectly horizontally (i.e., parallel to the ground) during its acceleration.

Answer 1

Answer:

40 J

Explanation:

Using equation of linear motion

v² = u² + 2as

where v is final velocity attain, u is initial velocity which is = 0 m/s since it is starting from rest, a is acceleration in m/s² and s is the distance covered

(20 m/s)² = 0 + 2 a × 1.2 m

400 / 2.4 = a

a = 166.67 m/s²

F = ma = 0.2 × 166.67 = 33.33 N

work done by the troubled youth = force × distance = 33.33 × 1.2 m = 40 J