Problem Statement The mass of sun is 2 × 10^30 kg and the mass of earth is 6 × 10^24 kg. If the average distance between the sun and the earth be 1.5 × 10^8 km, calculate the force of gravitation between them. Solution M1 = mass of the sun = 2 × 1030 kgM2 […]

## Solution to problems – class 9 – Set 1 Q35

Problem Statement What is the force of gravity on a body of mass 150 kg lying on the surface of the earth ? (Mass of earth = 6 × 10^24 kg; Radius of earth = 6.4 × 10^6 m; G = 6.7 × 10–11 Nm2/kg^2) Solution M1 = mass of the body = 150 kgM2 […]

## Solution to problems – class 9 – Set 1 Q34

Problem Statement Calculate the force of gravitation between two objects of masses 50 kg and 120 kg respectively kept at a distance of 10 m from one another. (Gravitational constant, G = 6.7 × 10 -11 Nm2 /kg^2) Solution M1 = 50 kg M2 = 120 kg Distance = r = 10 m Force of […]

## Solution to problems – class 9 – Set 1 Q31, Q32, Q33

Problem Statement 31) If a box is pushed horizontally on the floor with a force of 10 N and it moves 5 meter along the line of action of the force, then what is the work done by the Gravity or earth’s gravitational pull on that box ? Solution:The angle between gravity and the displacement […]

## Solution to problems – class 9 – Set 1 Q 28

Problem Statement A bullet is moving at a speed of 350 m/s when it embeds into a lump of moist clay. The bullet penetrates for a distance of 0.05 m. Determine the acceleration of the bullet while moving into the clay. (Assume a uniform acceleration.) Solution to physics problem Initial velocity of the bullet U=350 […]

## Solution to problems – class 9 – Set 1 Q 30

Problem Statement A baseball is popped straight up into the air and has a hang-time of 6 s. Determine the height to which the ball rises before it reaches its peak. (Hint: the time to rise to the max height is one-half the total hang-time.) Solution Hang time = Total time required for upward plus […]

## Solution to problems – class 9 – Set 1 Q 25

Problem Statement A bike accelerates uniformly from rest to a speed of 10 m/s over a distance of 30 m. Determine the acceleration of the bike. Solution U = 0 V = 10 m/s S= 30 m V2 = U2 + 2 a SAs U = 0, the equation becomes: V2 = 2 a SWhich […]

## Solution of Physics Numericals for class 9 (set 1 Q15)

Problem statement A force causes an acceleration of 10 m/s^2 in a body of mass 500 g. What acceleration would be caused by the same force in a body of mass 5 kg. Solution Case 1 mass = m=500 g = 0.5 kg Acceleration = a =10 m/s^2 Force = ma = 0.5 . 10 […]