Question

A 3.0-kg mass is moved at a constant speed by a force of 6.0 N. What is the change in the kinetic energy of the mass as it moves over a distance of 4.0 m in the direction of the force

Answer 1

The change in kinetic energy is zero (0).

Step-by-step explanation:

Given;

mass of the object, m = 3.0 kg

applied force, f = 6 N

distance through the object is moved, d = 4.0 m

The acceleration of the object is calculated as;

f = ma

a = f / m

a = (6) / 3

a = 2 m/s²

The constant speed through which this object is moved is calculated as;

v² = u² + 2ad

v² = 0 + 2 (2)(4)

v² = 16

v = √16

v = 4 m/s

The change in kinetic energy is calculated as;

ΔK.E = K.E(final) - K.E(initial)

ΔK.E = ¹/₂mv₂² - ¹/₂mv₁²

v₂ = v₁ = v (since the mass was moved at a constant speed; v)

ΔK.E = ¹/₂mv² - ¹/₂mv²

ΔK.E = 0

Therefore, the change in kinetic energy is zero (0).