Advertisements
Advertisements
Question
A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be 10 ms-2 , find :
the final velocity of the ball on reaching the ground .
Advertisements
Solution
Given, maximum height reached, s = 20 m
Acceleration due to gravity, g = 10 m/s2
Let v' be the final velocity of the ball on reaching the ground.
Considering the motion from the highest point to ground,
Velocity at highest point = 0 = Initial velocity for downward journey of the ball.
Distance travelled, s = 20m
Using the third equation of motion,
v2 - u2 = 2gs
or, v2 - 0 = 2 (10) (20) m/s
or, v2 = 400 m/s
or, v = 20 m/s
APPEARS IN
RELATED QUESTIONS
Choose the correct alternative:
Acceleration due to gravity increases/decreases with increasing depth. (assume the earth to be a sphere of uniform density).
How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 108 km.
Can two particles be in equilibrium under the action of their mutual gravitational force? Can three particles be? Can one of the three particles be?
Let V and E be the gravitational potential and gravitational field at a distance r from the centre of a uniform spherical shell. Consider the following two statements :
(A) The plot of V against r is discontinuous.
(B) The plot of E against r is discontinuous.
A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be 10 ms-2 , find :
the total time of journey of the ball .
Multiple Choice Question. Select the correct option.
The mass of earth is 6 × 1024 kg and radius of earth is 6.4 × 106 m. The magnitude of force between the mass of 1 kg and the earth is:
How will the force of gravitation between two objects change if the distance between them is:
Halved
All objects in the universe attract each other along the line joining their________.
Name and state the action and reaction in the following case:
A book lying on a table.
The distance-time values for an object moving along straight line are given below:
| Time (s) | Distance (m) |
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 27 |
