Question

A ball is projected from a point O as shown in figure.
It will strike the ground after (g = 10 m/s2)

(1) 4s
(2) 3s
(3) 2s
(4) 5s

A particle is thrown with a velocity of u m/s.
It passes A and B as shown in figure at time t, = 1 s
and t = 3 s. The value of u is (g = 10 m/s)

(1) 20 m/s
(3) 40 m/s
(2) 10 m/s
(4) 5 m/s

please answer step wise n with reason...thanq

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Answer 1

Answer:

i think option a is right

Answer 2

Answer:

Explanation:t=2usin thita /g

2×10/10×2=1sec

For downward motion

Initial velocity at y axis = 10 sin30°=5 m/s

a=g,h= 60

H= it+ 1/2at×t

60=5t+5t×t=(t_3)&(t +4)

T = 3

T= t+ t= 3+1= 4 sec