A box of mass 5.0kg is moving on a smooth ice surface with a velocity of 6.0m/s (right).?

Question

A constant force is applied for 3.0s and the box reaches final velocity of 12m/s (left). What was the applied force?

Answer 1

Mass of the box = 5 kg.

Initial Velocity = -6 m/sec.

Final Velocity = 12 m/sec.

Contact time = 3 sec.

Force = Mass * Accerlation

Accerlation = Change in Velocity / Change in time

Accerlation = (final velocity - Initial Velocity) / time.

a = (12 - (-6)) / 3

a = 18 / 3

a = 6 m/sec²

Accerlation is 6 m/sec².

We know that

Force = Mass * Accerlation

F = 5 * 6

F = 30 N.

Therefore the applied force is 30 N.