Question

A 10 kg box rests on the ground. What is the weight of the box? __ N

Answer 1

Explanation:

1. Mass of the box, m = 10 kg

Weight of an object is equal to the product of its mass and acceleration due to gravity. Its expression is given by :

W = mg

$W=10\ kg\times 9.8\ m/s^2$

W = 98 N

2. The normal force acting on an object is equal to its weight. So, N = 98 N

3. If the box is pushed to the left with 20 N of force and it is not moving, then there is a force acting on it which is called frictional force. The static friction force have magnitude of 20 N and it is acting in opposite direction of motion.

4. When the pushing force is increased to 40 N and the box begins to move, then the maximum static frictional force is equal to applied force i.e. 40 N.

Answer 2

The weight of an object is its mass times acceleration.

Weight of the box = (10kg)(9.81m/s^2) = 98.1N

If the box is at rest, then the normal force is equal to the weight of the box:

Normal force = 98.1N

If the box does not move, then the static friction force with 20 N is also 20N

Static Friction Force = 20N

If the box begins to move at 40, the maximum static friction force is equal to 40N

Maximum static friction force = 40N