Question

A projectile is an object projected into air with a velocity V so that it is moving under the influence of gravity. 

1. What is the shape of the path of projectile?

2. As a projectile moves in its path, is there any point along the path where the velocity and acceleration vectors are perpendicular to each other 

3. If E is energy with a projectile is projected.

(i) What is the Kinetic energy at the highest point. 

(ii) What is P.E at highest point?

Answer 1

1. Parabola

2. Yes, highest point

3. Energy with a projectile is projected:

(i) Kinetic energy E_k = 1/2mv²

Velocity at the highest point = Vcosθ

∴ K.E. at highest point = 1/2m(Vcosθ)²

= 1/2 mv²cos²θ

K.E. = E_k cos²θ

(ii) Potential energy at highest point,

P.E. = mgh

= mg \(\frac{v^2sin^2θ}{2g}\) = 1/2mv²sin²θ

P.E. = E_k sin²θ.