Table of Contents

- 1 Where is kinetic energy maximum in a projectile?
- 2 What happens the kinetic energy of an object when it speeds up?
- 3 What components of a projectile determine the kinetic energy the projectile has?
- 4 What affect the kinetic energy of an object?
- 5 Does kinetic energy increase as an object falls?
- 6 Where does kinetic energy go when it decreases?

## Where is kinetic energy maximum in a projectile?

In case of projectile motion, i) P.E is maximum at the highest point. ii) K.E of a projectile will be minimum (but not zero) at the highest point, because only vertical component of velocity is zero. K.E is maximum at the place of projection.

### What happens the kinetic energy of an object when it speeds up?

It turns out that an object’s kinetic energy increases as the square of its speed. A car moving 40 mph has four times as much kinetic energy as one moving 20 mph, while at 60 mph a car carries nine times as much kinetic energy as at 20 mph. Thus a modest increase in speed can cause a large increase in kinetic energy.

#### What components of a projectile determine the kinetic energy the projectile has?

(1) A projectile of mass (m) with an initial velocity of V has kinetic energy KE = (1/2) m (V^2). This initial KE remains CONSTANT throughout the projectile’s path and appears as the SUM of the GPE and KE of the mass at any point in the path.

**At what points is the kinetic energy of the projectile the same?**

As an object falls under the influence of gravity, kinetic energy and potential energy are equal everywhere/at the halfway point only. 10.

**How does the kinetic energy of an object change if the object’s speed is reduced by half?**

Kinetic Energy = ½mv², therefore if you reduce the velocity by half the kinetic energy will reduce to one quarter. For example: A particle with a mass of 1 and a velocity of 4 will have KE of 8. A particle with a mass of 1 and a velocity of 2 will have KE of 2.

## What affect the kinetic energy of an object?

Explain that there are two factors that affect how much kinetic energy a moving object will have: mass and speed.

### Does kinetic energy increase as an object falls?

As an object falls its potential energy decreases, while its kinetic energy increases. The decrease in potential energy is exactly equal to the increase in kinetic energy.

#### Where does kinetic energy go when it decreases?

When an object slows down, its kinetic energy decreases. As a result, some of its initial kinetic energy that the object has before slowing down is transformed into another form of energy.

**What is the initial kinetic energy of a projectile?**

the initial velocity of the ball. When the ball is at maximum height (hmax), its velocity is zero; therefore KE = 0 and PE = mghmax. If energy is conserved, the initial kinetic energy is equal to the final potential energy (KEi = PEf).