# Calculations Using Newton's 2nd Law

1. A ball that weights 5N falls on earth ...what is the net force that acts on the ball during the fall? Which is the force (including its direction) that the ball exercises on the land when it falls?

2. In the moon, the gravitational acceleration of the objects is around 1.67 meter/s2 How much does it weight in the moon an object that on earth has a mass of 2 kilograms? How much does it weight on earth? What is its mass in the moon?

3. Calculate the minimum distance in which a powerful car can reach 10m/s from its still position

4. Estimate the force that must be exercised by the ankles when they hit the floor after a 2 meter high jump. Why should you flex your legs?

5. Which is the magnitude of a horizontal force over a bullet of 8.5g to obtain an acceleration of 18,500 meter/s2 with this acceleration ... which is the speed of the bullet after a 2.35 cm movement from the initial standing still point?

6. A horizontal force not in equilibrium of 4600N(Newton) accelerate a car of 1650 kg from standing still point over a straight and horizontal road a) which is the acceleration of the car b) how long does it take to reach 21.1 m/s?

https://brainmass.com/physics/acceleration/calculations-newtons-2nd-law-22676

#### Solution Preview

1.) The gravitational force i.e., 5N acts as a net force on the ball during it's free fall.

F(during fall) = -5j --Answer

(vertical up ward direction considered as +ve direction and downward as -ve direction)

When ball strikes with the ground, it will apply the force on ground due to it's weight and change of momentum.

F = -5j - {m*v(1+e)/dt}j --Answer

Where, m = weight/g = 0.51 kg, v is the speed with which the ball strikes the ground, e.v is the factored speed by which the ball will bounce back, and dt is the time of contact of the ball with the ground.

After strike, if the ball stops, e = 0, if ball bounces back with same speed, e = 1, and if ...

#### Solution Summary

The solution includes calculations of force, distance, acceleration, and mass using Newton's 2nd Law.