Solution to problems – class 9 physics – Set 1 Q 60

Problem Statement 60) A metallic sphere of mass 2 kg and volume 2.5 x 10-4 m3 is completely immersed in water. Find the buoyant force exerted by water on the sphere. Density of water = 1000 kg/m3 Solution Volume of the water displaced = volume of the completely immersed sphere=2.5 x 10-4 m3 Mass of […]

Solution to problems – class 9 physics – Set 1 Q 57

Problem Statement 57) A ball X of mass 1 kg travelling at 2 m/s has a head-on collision with an identical ball Y at rest. X stops and Y moves off. Calculate the velocity of Y after the collision. Solution Initial momentum of X = 1×2 kg m/s = 2 kg m/s …………….(i) After collision […]

Solution to problems – physics class 9 – Set 1 Q 56

Problem Statement 56)A truck of mass 500 kg moving at 4 m/s collides with another truck of mass 1500 kg moving in the same direction at 2 m/s. What is their common velocity just after the collision if they move off together? Solution Total initial momentum = 500 x 4 + 1500 x 2 = […]

Solution to problems – class 9 physics – Set 1 Q 55

Problem Statement 55) A girl of mass 50 kg jumps out of a rowing boat of mass 300 kg on to the bank, with a horizontal velocity of 3 m/s. With what velocity does the boat begin to move backwards ? Solution As no initial velocity is given in the problem statement, we will consider […]

Solution to problems – class 9 physics – Set 1 Q 53

Problem Statement 53) Calculate the height of a water column which will exert on its base the same pressure as the 70 cm column of mercury. Density of mercury is 13.6 g/cm^3. Solution (continuing with cgs system data)Pressure of mercury column is hdg = 70 x 13.6 x g ……..(1) let the height of water […]

Solution to problems – class 9 physics – Set 1 Q52

Problem Statement 52) The area of base of a cylindrical vessel is 300 cm^2. Water (density = 1000 kg /m^3) is poured into it up to a depth of 6 cm. Calculate: (a) the pressure and (b) the thrust of water on the base. (g = 10 m/ s^2). Solution Pressure = hdg=(6/100)x1000x10 = 600 […]

Solution to problems – class 9 – Set 1 Q 48

Problem Statement 48) A ball is thrown vertically upwards from the top of a tower with an initial velocity of 19·6 m/s. The ball reaches the ground after 5 s. Calculate: (i) the height of the tower, (ii) the velocity of ball on reaching the ground. Take g = 9·8 m/s^2 Follow my blog with […]

Solution to problems – class 9 – Set 1 Q47

Problem Statement 47) A pebble is dropped freely in a well from its top. It takes 20 s for the pebble to reach the water surface in the well. Taking g = 10 m/s^2 and speed of sound = 330 m/s, find: (i) the depth of water surface, and (ii) the time when echo is […]

Solution to problems – class 9 – Set 1 Q37, 38, 39, 40, 41

solution of 5 numericals from Q set 1 for class 9. Motion under gravity is the primary focus of the following problems. Upward and downward movement, maximum height reached, time to reach the maximum height, velocity just before touching the ground etc are the touched upon points of these sort of numerical problems in physics. […]

Solution to problems – class 9 – Set 1 Q36

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 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 27

Problem Statement A bullet leaves a rifle with a muzzle velocity of 600 m/s. While accelerating through the barrel of the rifle, the bullet moves a distance of 0.8 m. Determine the acceleration of the bullet (assume a uniform acceleration). Solution Initial velocity of the bullet U=0 Final velocity of the bullet = muzzle velocity […]

Solution to problems – class 9 – Set 1 Q 26

Problem Statement A race car accelerates uniformly from 25 m/s to 50 m/s in 5 seconds. Determine the acceleration of the car and the distance traveled. Solution Acceleration a = (50-25)/5 a = 5 m/s2 To find out the distance travelled we will use the equation V2 = U2 + 2 a S where S=( […]

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 29

Problem Statement A plane has a takeoff speed of 100 m/s and requires 1500 m to reach that speed. Determine the acceleration of the plane and the time required to reach this speed. Solution It starts from rest. So initial velocity U = 0  Final velocity = take off velocity = V = 100 m/s   […]

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 18

Problem Statement A car starts from rest and accelerates uniformly over a time of 7 seconds for a distance of 98 m. Determine the acceleration of the car. Solution Distance travelled: S = ut + ½ a t2 As u = 0, the equation becomes    S = ½ at2  so, a = 2S/t2 …..(1) t […]

Solution to problems – class 9 – Set 1 Q 20

Problem Statement An airplane accelerates down a runway at 4 m/s2 for 30s until is finally lifts off the ground. Determine the distance traveled before takeoff. Solution S = ut + ½ a t2as u = 0, the equation becomes    S = ½ a t2  a = 4 m/s2   t = 30 secs So the distance […]

Solution to problems – class 9 – Set 1 Q 21

Problem Statement A feather is dropped on the moon from a height of 10 meters. The acceleration of gravity on the moon is one sixth of that on the earth. Determine the time for the feather to fall to the surface of the moon. Solution Acceleration of gravity on the moon = 10/6 m/s2 = […]

Solution to problems – class 9 – Set 1 Q 22

Problem Statement If a rocket-powered sled is accelerated to a speed of 400 m/s in 2 seconds, then what is the acceleration and what is the distance that the sled travels? Solution Acceleration a = (v-u)/t = (400 – 0)/2 = 200 m/s2 Distance travelled by the sled S = ut + ½ a t2 […]

Physics questions and answers for class 9 cbse icse

Physics questions and answers for class 9 for CBSE and ICSE boards – selected numericals and fundamental questions are being published under this super set. Students of the Upper classes will also get benefitted if they try these. Solutions will also be provided. Here is the first set. More will come. visit us. Assignments 1.) […]

Solution of Physics Numericals for class 9 (set 1 Q11)

Problem Statement A force acts for 10 s on a stationary body of mass 100 kg after which the force ceases to act. The body moves through a distance of 100 m in the next 5 s. Calculate (i) the velocity acquired by the body, (ii) the acceleration produced by the force, and (iii) the […]

Velocity time graph – comprehensive Guide

The velocity-time graph is defined as a graphical representation of the velocity of a body in motion with respect to time. Generally, velocity is assigned to the y-axis, and time is pointed on the x-axis. This graph type is also written as a v-t graph or velocity-time graph. The diagram below depicts a few velocity-time […]

Contact Forces between blocks – Application of Newton’s laws

Application of newton’s laws: Newton’s laws of motion give us concepts of force (first law), measurement of force with its equation (second law), and the reaction of force (3rd law). Today we will discuss an interesting topic of mechanics – the application of Newton’s laws. It will cover a few interesting applications of Newton’s Laws […]

Physics problems – Solutions of selected numericals(set 1)

Physics Problem set with Solution Some of the posts in this blog include sample physics problem sets along with the post content. Readers can always try those. We have decided to publish the solutions to selected problems from different sets/posts, as we have done in this post. Physics Problem Q set source: (based on the […]

Physics Numerical Problems and Question Sets

Physics Numerical Problems & Q sets This physicsteacher blog publishes sets of physics numerical problems. We are in a process to publish many such physics problem sets here in this blog itself. And on top of this, we are going to write how to solve those problems as well with hints, solutions and answers. These […]

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