Question

A particle is projected from horizontal surface with a velocity of 20 m per second at an angle of 60 degree with the horizontal. When it hits the horizontal surface, its velocity makes an angle of 30 degree with the horizontal. Apart from gravity,a horizontal force acts on the particle during the motion. The speed of particle when it hits the ground is

Answer 1

Answer:

The speed of particle when it hits the ground is 1.7279 m/s

Explanation:

Velocity of the particle = 2 m/s

Angle with the horizontal (Ф)= 60 degrees

Horizontal component of velocity = 2cosФ = 1 m/s

Vertical component of velocity = 2sinФ = √3

Here the horizontal force of gravity acts on it

Hence, by kinematic equation we have

v = u + at

0 = √3 - 9.8t  (Because at top position the velocity of the particle will be 0)

√3= 9.8t

t= 0.176 sec

Total time for it to be in the air T=2t = 2*0.176 = 0.352 sec

Hence on reaching the ground the vertical velocity of the particle will be,

v = u + at

v =  √3 - (9.8)T

v = √3 - (9.8)0.352

v = -1.717 m/s  (Negative sign indicates that the velocity is downwards)

Since the angle on reaching the ground is 30 degree

Therefore,

vertical component/ horizontal component = 30

1.717/ x = 30

x = 0.0572 m/s

Horizontal component of velocity when the particle hits the ground is 0.0572 m/s while the Vertical component is 1.727 m/s

Hence the final velocity on hitting the ground is

V =√( Horizontal component²+Vertical component²)

V = √(0.0572²+1.727²)

V = 1.7279 m/s

Answer 2

Explanation:

I hope you understand that