In projectile motion the modulus of rate of change of speed

Question

In projectile motion the modulus of rate of change of speed (A) is constant (B) First increases then decreases (C) First decreases then increases (D) increases continuously

Tardigrade Admin · Accepted Answer

We know that speed at any instant is the magnitude of instantaneous velocity.
And, the modulus of rate of change of speed is equal to modulus of rate of change of velocity.

In projectile motion, rate of change of velocity that is acceleration is

a =

- g \hat{j} = - 10 \hat{j} m / s^{2}

that is downward
Hence the modulus of rate of change of speed is

10 m / s^{2} =

constant

Q. In projectile motion the modulus of rate of change of speed

is constant

First increases then decreases

First decreases then increases

increases continuously