An iron bal of mass 20kg is rolling on a flat surface. On applying force, the velocity change from 17ms to 27m/s in 5s. Calculate the magnitude of the force. (Ans:40N)

40 N

Explanation:

We first need to calculate the acceleration of the tron ball.

Since acceleration, a = (v - u)/t where u = initial velocity of iron ball = 17m/s, v = final velocity of iron ball = 27m/s and t = time taken for the change in velocity = 5 s.

So, a = (v - u)/t

= (27 m/s - 17 m/s)/5 s

= 10 m/s ÷ 5 s

= 2 m/s²

We know force on iron ball, F = ma where m = mass of iron ball = 20 kg and a = acceleration = 2 m/s²

So, F = ma

= 20 kg × 2 m/s²

= 40 kgm/s²

= 40 N

So, the magnitude of the force on the iron ball is 40 N.

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.