Question

A body is projected with a velocity of 40 m/sec, and at an angle 30 . The time it takes to be at a height of 20 m
is (g = 10 ms-2)

Answer 1

Answer:

1.9 , 2.3 sec it is at 40 .

Explanation:

studying Motion in Y axis

resolving Component of Vo for Y axis = 40 . Sin 30= 20.

acceleration in Y axis = -10 ... gravity alone.

40 =; 20 t + 5 x 10x T^2

5 t^2+2t = 4

( t+ 1/5)^2=;4 + 1/25 = 4.04= ( 2.01)^2

t = 2.01 +/-0.2 =; 1.9 , 2.3 sec