Ncert – class 9- science – Chapter 7 – Motion 1 Welcome to your Ncert - class 9- science - Chapter 7 – Motion 1 1. A body of mass 5 kg having a velocity of 80ms−1 experiences a force in the opposite direction. The body is brought to rest in 8 sec. What is the retardation produced by the force? 15ms-2 25ms-2 10ms-2 20ms-2 None 2. For a body performing motion with uniform speed, the distance-time graph is Straight line parallel to Y-axis Curved line Straight line inclined to the time axis None 3. A body starting with initial velocity u comes back to the starting point in t seconds. Then the acceleration is -2 u/t t/2u 2 /t u/t None 4. Starting from rest objects 1 falls freely for 4 seconds and object 2 falls freely for 8 seconds .Compared to object 1, object 2 falls half as far twice as far four times as far sixteen times as far None 5. Is it possible for an object's velocity to increase while its acceleration decreases? Yes, an example would be a falling object in a viscous medium, where the acceleration continuously decreases but velocity increases until a certain point. No, because velocity and acceleration must always be in the same direction. No, because if acceleration is decreasing the object will be slowing down. No, this is impossible because of the way in which acceleration is defined. None 6. The acceleration of an object moving in a straight line can be determined from the Slope of the velocity-time graph Slope of the distance-time graph Area between the velocity-time graph and time axis Area between the distance-time graph and time axis None 7. A particle moves with constant acceleration for 6 seconds after starting from rest. The distance travelled during the first three consecutive 1 seconds interval is in the ratio? 1 : 1 : 1 1 : 5 : 9 1 : 2 : 3 1 :3 : 5 None 8. A conveyor belt is moving horizontally at a speed of 4 m/sec with a box of mass 20 kg on it. The box suddenly drops off the conveyer belt to the ground and it takes 0.1 second for the box to come to rest. Considering the height of the conveyer belt to be negligible, the distance moved by the box in the conveyor belt is: 0.2 0.8 0 0.4 None 9. Water drops fall at regular intervals from a roof at of 125 m from the ground. At an instant when 11th drop is about leave the roof and 1st drop is at a height of 45 m from the ground at that instant the dist of 10th drop from the roof is (g=10 m/s ^2) 0.80m 0.40 m 0.20m 1.2m None 10. A car accelerates uniformly from 18km/h to 36km/h in 5s. The distance covered by the car will be 1m 18m none of theses 37.5m None 11. A body was initially moving with 10 m/sec and it starts acceleration with 2 m/sec ^2, the distance covered by it in 10 sec will be 200 m 250 m 100 m 150 m None 12. On the distance-time graph, the Y-axis should be labeled as Distance Speed Displacement Time None 13. A particle has a velocity u towards east at t = 0. Its acceleration is towards west and is constant, Let \(X_{A}\) and \(X_{B}\) be the magnitude of displacements in the first 10 seconds and the next 10 seconds. \(X_{A} < (X_{B}\) \(X_{A} = (X_{B}\) the information is insufficient to decide the relation of \(X_{A} < (X_{B}\) \(X_{A} > (X_{B}\) None 14. A train is travelling at a speed of 108 km/h. Brakes are applied so as to produce a uniform retardation of 1 m/s^2. Find how far the train will go before it is brought to rest : 800 m 450 m 1050 m 1000 m None 15. A sprinter completes a round on a circular path of circumference 400 m, what is his displacement? 100 m Zero 200 m 400 m None 16. In a motion with constant acceleration the velocity is reduced to zero in 5 seconds and after covering a distance of 100 m. The distance covered by the particle in next 5 second will be :- 100 m 250 m 500 m zero None 17. In a damped oscillator, the mass of the oscillator is m = 200g, force constant is K = 90N/m and the damping constant b is 40 g/s. Find the time taken for its mecharical energy to drop to half its initial value 6.93s 3.46s 0.3s 0.208 s None 18. Which of the following statements is correct for a particle travelling with a constant speed? Its acceleration is zero. It covers equal distances in unequal time intervals. It does not change its direction of motion. Its position remains constant as time passes. None 19. A body moving from rest with uniform acceleration travels a distance 'X' in the first t seconds and travels a distance 'Y' with same acceleration in the next '2t' seconds, then Y = (1/2)X Y = 3X Y = 2X Y = 4X None 20. A water drop falls at regular intervals from a tap 99 m above the ground. The fourth drop is leaving the tap at the instant, the first drop touches the ground. How high is the third drop at that instant? 4 m 6 m 2 m 8 m, None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
