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 initial velocity of the ball.
Solution
Given, maximum height reached, s = 20 m
Acceleration due to gravity, g = 10 m/s2
Let 'u' be the initial velocity.
At the highest point, velocity = 0
Using the third equation of motion,
v2 - u2 = 2gs
or, 0 - u2 = 2 (10) (20) m/s
or, u2 = -(400) m/s ...[Negative sign indicates that the motion is against gravity]
or, u = 20 m/s
APPEARS IN
RELATED QUESTIONS
Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth = 6 × 1024 kg and of the Sun = 2 × 1030 kg. The average distance between the two is 1.5 × 1011 m.
A person sitting in a chair in a satellite feels weightless because
A body is suspended from a spring balance kept in a satellite. The reading of the balance is W1 when the satellite goes in an orbit of radius R and is W2 when it goes in an orbit of radius 2 −R.
Write an expression for the gravitational force of attraction between two bodies of masses m1 and m2 separated by a distance r.
The acceleration produced by a force in an object is directly proportional to the applied _________ And inversely proportional to the _________ Of the object.
How will the force of gravitation between two objects change if the distance between them is:
Made four times
A ball is thrown up with a speed of 4.9 ms-1.
Prove that the time of ascent is equal to the time of descent.
Name and state the action and reaction in the following case:
A book lying on a table.
State the law of gravitation. Why is it called universal?
Law of gravitation gives the gravitational force between
