Question

17. For how long should a force of 130 N be applied to an object of mass 50 kg to change its speed from 20 m/s to 60 m/s?

Answer 1

Answer:

c. 15.4 s

Explanation:

Given the following data;

Mass, m = 50kg

Force, F = 130N

Initial velocity, u = 20m/s

Final velocity, v = 60m/s

To find the time;

First of all, we would solve for acceleration using the formula below;

Force = mass * acceleration

130 = 50*acceleration

Acceleration = 130/50

Acceleration = 2.6m/s²

Now, we would use the first equation of motion to find the time.

V = U + at

60 = 20 + 2.6t

2.6t = 60 - 20

2.6t = 40

t = 40/2.6

Time, t = 15.39 ≈ 15.4 seconds.