A truck starts from rest down a hill with a constant acceleration. It achieves 400 meters in 20 seconds. If the weight of the truck is 7 tons then what will be the force acting on it?

Explanation

For motion with uniform acceleration, the equation is: s = ut + ½at² Here, since u = 0: s = ½at² So, 400 = ½ × a × (20)² 400 = ½ × a × 400 400 = 200a a= 400/200 = 2 m/s² Therefore, the acceleration of the truck is: a = 2 m/s² Now, according to Newton’s second law of motion: F = ma Mass = 7 tonnes = 7000 kg So, F = ma = 7000 × 2 = 14000 N Thus, the force acting on the truck will be 14000 N. Compared to the Earth, gravity on the Moon is about 1/6 as much. Therefore, an object’s weight on the Moon is 1/6 of its weight on Earth. Weight = 1/6 (Weight on Earth) = (1/6) × 100 = 16.7 N