Answer :
Final answer:
The horizontal force required to pull a 30 kg mass at constant velocity on a level surface with a coefficient of kinetic friction of 0.3 is approximately 88 N.
Explanation:
To find the horizontal force needed to pull a mass of 30 kg at constant velocity on a level surface with a coefficient of kinetic friction (μk) equal to 0.3, we can use the formula for friction: Ffriction = μk × N, where N is the normal force. Since the surface is level, the normal force is equal to the gravitational force on the mass, which is N = mg where m is the mass and g is the acceleration due to gravity (9.8 m/s2).
First, we calculate the normal force: N = 30 kg × 9.8 m/s2 = 294 N. Next, we apply the coefficient of kinetic friction: Ffriction = 0.3 × 294 N = 88.2 N. To maintain constant velocity, the applied force must equal the frictional force, so the necessary horizontal force is approximately 88 N.
Therefore, the correct answer is b) 88 N.
