Physics, asked by BrainlyHelper, 1 year ago

A ball is thrown horizontally from a point 100 m above the ground with a speed of 20 m/s. Find (a) the time it takes to reach the ground, (b) the horizontal distance it travels before reaching the ground. (c) the velocity (direction and magnitude) with which it strikes the ground.Concept of Physics - 1 , HC VERMA , Chapter "Rest and Motion : Kinematics

Answers

Answered by prmkulk1978
178
Solution :
This case is a projectile fired horizontally from a height of h
g=9.8m/s2

a)Time it takes to reach the ground,
height=100m
t=
√2h/g
t=√2x100/9.8=√200/9.8=4.51 sec

b)The horizontal distance it travels before reaching the ground:
speed=u=20m/s
x=ut=20x 4.5 =90m

c)Horizontal velocity remains constant through out the journey.

At "A", vx=20m/s
vy=u+at
=0+9.8 x 4.5=44.1m/s

Final resultant velocity=vr=
√(44.1)²+20²=48.42 m/s
tanβ=vy/vx=44.1/20=2.205
β=tan⁻¹(2.205)=66⁰
∴The ball strikes the ground with a velocity of  48.42m/s at an angle of 66° with horizontal.
Answered by SulagnaRoutray
30

Answer:

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