Physics CBSE 9

Worksheet Force and Motion CBSE 9 Physics Q1. A force cannot do one of the following: ( a ) can change the shape of a body, ( b ) can accelerate a body, ( c ) can change the direction of motion of a body, ( d ) can change colour of a body. Q2. A box lying on a frictionless floor is subjected to two forces along one straight horizontal line. The magnitude of the force acting to the right is 200 N and that of acting to the left is is 150 N.The unbalanced force on the box is : ( a ) 350 N to the right, ( b ) 350 N to the left, ( c ) 50 N to the right, ( d ) 50 N to the left. Q3. There is a resistance offered by an object to its state of motion. ( true / false ). Q4. If a body is at rest it tends to remain at rest ; if it is moving it tends to keep moving.This property of an object is called its …………………. Q5. Mass is measure of inertia. (true / false ). Q6. Which of the following objects has largest inertia : ( a ) a book ( b ) a car ( c ) a railway train ( d ) common pin. Q7. The SI unit of mass is : ( a ) gram ( b ) kilogram ( c ) milligram ( d ) microgram. Q8. A body moves equal distances in equal intervals of time in a straight line then it has uniform motion. ( true / false ). Q9 A body continues to remain in its state of rest or uniform motion along a straight line unless acted on by an external force. This is Newton’s second law of motion. ( true / false ). Q10. An apple is thrown out of window of a space ship that is Moving in a gravity free space then the apple will : ( a ) accelerate along a straight line. ( b ) reduce its speed gradually ( c ) change its direction of motion ( d ) keep moving uniformly in a straight line. Q11 The momentum of a body is the product of its mass and velocity (true / false ). Q12 The SI unit of momentum is ( true / false ). Q13 An airplane of mass 12000 Kg is moving with velocity 720 Km / hr. Calculate its momentum in SI unit. Q14 Newton’s second law of motion is : ( a ) Action and reaction are equal and opposite. ( b ) Rate of change of momentum is directly proportional to the applied force and occurs in the direction of the force. ( c ) A body continues to remain in its state of rest or uniform motion along a straight line unless acted on by an external force. ( d ) Mass is measure of inertia. Q15. A constant force acts on a body of mass 4 Kg for a duration of 5 s and changes its velocity from 12 m/s to 22 m/s.Find the magnitude of the applied force. If the force were applied for 4 s, what would have been its final velocity ? Q16 Which would require a greater force – accelerating a mass of 8 Kg at 4 or a 4 Kg mass at 10 ? Q17 A bullet of mass 4 g is fired horizontally with a velocity of 800 from a pistol of mass 1 Kg. What is the recoil velocity of the pistol ? Q18 Velocity – time graph of a space ship of mass 1200 Kg moving along a straight line is shown below. How much force is acting on it ? Q18 Gopal whose mass is 50 Kg jumps with horizontal velocity of 4 m/s onto a stationary cart with frictionless wheels. The mass of the cart is 8 Kg . What is the velocity of the cart in which Gopal now stands ? Assume that the cart is on the frictionless horizontal floor. Q19 Two players A and B of opposite football teams are running towars each other with velocities 8 m/s and 12 m/s respective- ly collide and get entangled. Their masses are respectively 40 and 50 Kg. What is their common velocity after the collision ? Benjamin Academia 3 020810CBSE9WS