Newton's Third Law and Free-Body Diagrams — Practice Questions
Free NEET Physics multiple-choice questions on Newton's Third Law and Free-Body Diagrams. Attempt each question and reveal the answer with a full explanation.
Two masses m 1 = 5 kg and m 2 = 10 kg are connected at the ends of a massless string that passes over a frictionless pulley. The acceleration of the system is: ( g = 10 m/s 2 ) 3.33 m/s 2 5.0 m/s 2 2.5 m/s 2 10 m/s 2 A bob is whirled in a horizontal plane by means of a string with an initial speed of rpm. The tension in the string is T . If speed becomes 2 while keeping the same radius, the tension in the string becomes: T 4T T 4 2 T A point mass m is suspended from a ceiling by a light string of length l . It is pulled by a horizontal force F such that the string is inclined at 45 to the vertical. The value of F is: mg mg/ 2 2 mg 2mg Two masses of 1 kg and 5 kg are attached to the ends of a massless string passing over a frictionless pulley. The tension in the string is: ( g = 9.8 m/s 2 ) 16.3 N 19.6 N 9.8 N 32.6 N A light string passes over a frictionless pulley. To one end a mass of 5 kg is attached and to the other a mass of 3 kg is attached. The tension in the string is: ( g = 10 m/s 2 ) 37.5 N 20 N 80 N 40 N A rope of length L and mass M is hanging from a rigid support. The tension in the rope at a distance y from the support is: Mg(1 - y/L) Mgy/L Mg Mg(1 + y/L) A mass m is suspended by a string. It is pulled aside by a horizontal force F so that the string makes an angle with the vertical. The tension in the string is: mg / mg / mg F A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity . The force exerted by the liquid at the other ends is:- ML 2 2 ML 2 2 ML 2 ML 2 2 2 A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8 10 -4 J by the end of the second revolution after the beginning of the motion ? 0.1 m/s 2 0.15 m/s 2 0.18 m/s 2 0.2 m/s 2 What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop ? gR 2gR 3gR 5gR A car is negotiating a curved road of radius R. The road is banked at an angle . the coefficient of friction between the tyres of the car and the road is s . The maximum safe velocity on this road is :- gR 2 s + 1 - s gR s + 1 - s g R s + 1 - s g R 2 s + 1 - s The force of action and reaction mentioned in Newton's third law: Always act on different bodies Always act on the same body Are equal in magnitude and same in direction Cancel each other out A cyclist on a level road takes a sharp circular turn of radius 3m (g=10ms -2 ) . If the coefficient of static friction between the cycle tyres and the road is 0.2, at which of the following speeds will the cyclist not skid while taking the turn? 14.4 km h -1 7.2 km h -1 9 km h -1 10.8 km h -1 A body initially at rest and sliding along a frictionless track from a height h (as shown in the figure) just completes a vertical circle of diameter AB = D. The height h is equal to 7 5 D D 3 2 D 5 4 D A bob of heavy mass m is suspended by a light string of length l . The bob is given a horizontal velocity v 0 as shown in figure. If the string gets slack at some point P making an angle from the horizontal, the ratio of the speed v of the bob at point P to its initial speed v 0 is: ( 2+3 ) 1 2 ( ) 1 2 ( 1 2+3 ) 1 2 ( 2+3 ) 1 2 Two bodies of mass 4 kg and 6 kg are tied to the ends of a massless string. The string passes over a pulley which is frictionless. The acceleration of the system in terms of acceleration due to gravity ( g ) is: g/5 g/2 g/10 g A stone tied to the end of a string of 1 m long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolution in 44 seconds, what is the magnitude and direction of acceleration of the stone- 2 ms -2 and direction along the tangent to the circle 2 ms -2 and direction along the radius towards the centre. 2 4 ms -2 and direction along the radius towards the centre. 2 ms -2 and direction along the radius away from the centre. The circular motion of a particle with constant speed is- Periodic and simple harmonic Simple harmonic but not periodic Neither periodic nor simple harmonic Periodic but not simple harmonic A car runs at a constant speed on a circular track of radius 100 m, taking 62.8 seconds for every circular lap. The average velocity and average speed for each circular lap respectively is: 0, 0 0, 10 m/s 10 m/s, 10 m/s 10 m/s, 0 Two particles A and B are moving in uniform circular motion in concentric circles of radii r A and r B with speed v A and v B respectively. Their time period of rotation is the same. The ratio of angular speed of A to that of B will be : 1 : 1 r A : r B v A : v B r B : r A A mass m is attached to a thin wire and whirled in a vertical circle. The wire is most likely to break when: inclined at an angle of 60 from vertical the mass is at the highest point the wire is horizontal the mass is at the lowest point A particle moving with uniform speed in a circular path maintains: Constant velocity Constant acceleration Constant velocity but varying acceleration Varying velocity and varying acceleration