Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

A ball is thrown vertically upwards and rises to a height of 126.5 m. Calculate the (i) velocity by which the ball was thrown upwards and (ii) the time taken by the ball to reach the highest point. (Given is g = 9.8 ms–²) At Least 100 to 150 words
Asked by Aryungupta.espn | 30 Dec, 2019, 03:34: PM
answered-by-expert Expert Answer
h = 126.5 m 
 
i) 
v2 - u2 = 2as 
As the ball is moving against the gravity when thrown upward, 
 
v2 - u2 = 2gh
Thus, 
0 = u2 + 2 (-9.8) × (126.5) ... (negative sign of 'g' indicate that the object is moving against the gravity)
u2 =  2479.5
Thus, 
u = 49.79≈ 50 m/s
 
Thus, the velocity by which the ball must be thrown upward is 49.79 m/s
 
ii) time taken by the ball to reach the highest point is given as, 
v = u + gt
Thus, 
0 = 49.79 + (-9.8) x t 
Thus, 
t = 5.08 s
Answered by Shiwani Sawant | 30 Dec, 2019, 06:39: PM

Application Videos

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 9 - Physics
A boy throws a steel ball straight up. Consider the motion of the ball only after it has left the boy's hand but before it touches the ground and assume that forces exerted by the air are negligible. For these conditions, the force(s) acting on the ball is (are): a. A downward force of gravity along with a steadily decreasing upward force b. A steadily decreasing upward force from the moment it leaves the boy's hand until it reaches its highest point on the way down there is a steadily increasing downward force of gravity as the object gets closer to the earth c. Constant downward force of gravity along with an upward force that steadily decreases until the ball reaches it highest point on the way down there is only a constant downward force of gravity d. Constant downward force of gravity only
Asked by harshsrivastava8896606 | 17 Apr, 2023, 01:47: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
what is the weight of an object at the centre of the earth 
Asked by advscjaglan | 09 Aug, 2022, 08:22: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
what is Newton's contribution on gravitation?
Asked by munendramishra478 | 12 Jul, 2022, 08:42: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
two satellites of a planet have period 32 day and 256 days if the radius of orbit of former is R, find the orbital radius of the letter
Asked by rk7213908 | 31 Mar, 2022, 12:28: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
weight of the body is zero in free fall why?
Asked by rk7213908 | 21 Feb, 2022, 04:48: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
my doubt is the value of G is 60673multiply10-11power but why we use some no in some different numericals like use of 6.6, some times 6.7 why please ans this ques now 🙏
Asked by mannatjohn920 | 15 Feb, 2022, 09:57: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
Find the force of gravitational attraction between the earth (m = 6 x 1024 kg) and 80 kg man if he is standing at sea level. The distance of man from earth's center is 6.38 x 106 m.
Asked by sudiptaroy0607 | 08 Jan, 2022, 04:59: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
a stone is released from the top of the tower of height 19.6 m calculate its final velocity just before touching the ground
Asked by mj2692076 | 31 Dec, 2021, 04:11: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
what is gravitation
Asked by kalpanatiwaritiwari7030 | 22 Dec, 2021, 07:35: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
how does the force of gravitation between two objects change when the distance between them is reduced to half
Asked by sonalichavan03.bpps | 19 Dec, 2021, 08:19: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×