Question

A projectile is projected with speed 60 m/s at an angle 60° from the horizontal. After some time
projectile is moving at angle 30° with horizontal, what
is value of
d|v|/dt (change in velocity) at this instant? (Given g = 10 m/s2)

Answer 1

Given:  projectile is projected with speed 60 m/s, after some time projectile is moving at angle 30° with horizontal

To find: value of  d|v|/dt

Solution:

• First, we have given that innitial velocity, and angle of inclination as well.

• After that the projectile changed and angle became 30 degree with horizontal, So components of acceleration becomes g sin 30 and g cos 30.

• So the value of d|v|/dt will be:

             d|v|/dt = g sin 30

• And the value of d v(vector) /dt will be:

              d (v(vector)) /dt = g cos 30

• g sin 30 is causing the change in the magnitude of velocity while g cos 30 is the reason for the change in the direction.

Answer:

          Value of  d|v|/dt (change in velocity) at this instant is g sin 30