Q. 304.5( 8 Votes )
Prove that if a body is thrown vertically upwards, then the time of ascent is equal to the time of descent.
u = Initial velocity
v = Final velocity
h = Height attained
a = acceleration
t = time
Ball thrown upward with velocity u. So, v = 0 at maximum height h. Also a = -g
Now, using v = u + at
0 = u - g
Where = time of ascent
Also, by using
u = …..2
From equations 1 and 2, we get,
Ball comes down from height h. So, u = 0 and a = g.
So, using v = u + at
v = g …..3
Where = Time of descent
v = …..4
From equations 3 and 4, we get,
From equations A and B, we see that,
Rate this question :
It was raining heavily one day. Prateek made a paper boat and started playing with it in a water pool at road side. He then got his toys and dolls and made them boat riders the boat sank in water. Prateek did not lose courage. He made another boat and used lighter toys as passengers and this time boat did not sink in water.
(a) Why did not sink when loaded with dolls and toys?
(b) Which force is exerted by water on objects immersed in it?
(c) What qualities are shown by Prateek?Together with Science
A rectangular wooden block has length, breadth and height of 50 cm, 25 cm and 10 cm, respectively. This wooden block is kept on ground in three different ways, turn by turn. Which of the following is the correct statement about the pressure exerted by this block on the ground?
A. The maximum pressure is exerted when the length and breadth from the base
B. The maximum pressure is exerted when length and height from the base
C. The maximum pressure is exerted when breadth and height form the base
D. The minimum pressure is exerted when length and height form the baseLakhmir Singh & Manjit Kaur - Physics
Name the quantity whose one of the units is Pascal (Pa).Lakhmir Singh & Manjit Kaur - Physics
A body lying on a mattress stands up on it. He observes that the mattress is now depressed deeper down. Why does this happen?Together with Science
No one can sink in the Dead Sea. Do you agree? Give reason.Together with Science