Free NEET Physics multiple-choice questions on Newton's First Law & Inertia. Attempt each question and reveal the answer with a full explanation.
A block of mass m is pulled along a horizontal surface by a force F at an angle with the horizontal. The normal force exerted by the surface on the block is: mg - F mg + F mg - F mg A frame of reference moving with a constant velocity is: Inertial Non-inertial Accelerated None of these The mass of lift is 2000 kg. When the tension in the supporting cable is 28000 N, then its acceleration is : 14 ms -2 upwards 30 ms -2 downwards 4 ms -2 upwards 4 ms -2 downwards Three blocks with masses m , 2m and 3m are connected by strings, as shown in the figure. After an upward force F is applied on block m , the masses move upward at constant speed v . What is the net force on the block of mass 2 ,m ? ( g is the acceleration due to gravity) Zero 2 ,mg 3 ,mg 6 ,mg The force 'F' acting on a particle of mass 'm' is indicated by the force-time graph shown below. The change in momentum of the particle over the time interval from zero to 8 s is :- 24 Ns 20 Ns 12 Ns 6 Ns A particle moving with velocity V is acted by three forces shown by the vector triangle PQR. The velocity of the particle will : Change according to the smallest force QR Increase Decrease Remain constant 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 (see figure). The acceleration of the system in terms of acceleration due to gravity (g) is : g/2 g/5 g/10 g A ball of mass 0.15 kg is dropped from a height 10 m, strikes the ground and rebounds to the same height. The magnitude of impulse imparted to the ball is ( g = 10 m/s 2 ) nearly 4.2 kg m/s 2.1 kg m/s 1.4 kg m/s 0 kg m/s A horizontal force 10 N is applied to a block A as shown in figure. The mass of blocks A and B are 2 kg and 3 kg respectively. The blocks slide over a frictionless surface. The force exerted by block A on block B is : Zero 4 N 6 N 10 N The magnitude and direction of the acceleration produced in a body of mass 5 kg when two mutually perpendicular forces 8 N and 6 N act on it, are respectively: 2 m s -2 ; -1 (3/4) with 8 N force 2 m s -2 ; -1 (4/3) with 8 N force 2 m s -2 ; -1 (3/4) with 6 N force 20 m s -2 ; -1 (4/3) with 8 N force A block of mass m is placed on a smooth inclined plane of inclination . The force required to keep the block stationary relative to the plane if the plane is accelerating horizontally is ma . The value of a is: g g g g When a horse pulls a cart, the force that helps the horse to move forward is the force exerted by: The ground on the horse The cart on the horse The horse on the ground The horse on the cart Three forces acting on a particle of mass m are represented by the sides of a triangle ABC taken in order. The particle will move with: constant velocity constant acceleration varying acceleration decreasing velocity A person standing on the floor of an elevator drops a coin. The coin reaches the floor of the elevator in time t 1 when the elevator is stationary and in time t 2 when the elevator is moving uniformly. Then: t 1 = t 2 t 1 > t 2 t 1 < t 2 t 1 may be greater or less than t 2 A man of mass 50 kg stands on a weighing scale in a lift which is moving with an upward acceleration of 1.2 m/s 2 and then with a downward acceleration of 1.2 m/s 2 . The reading of the scale in these two cases respectively are: ( g = 9.8 m/s 2 ) 550 N, 430 N 430 N, 550 N 500 N, 500 N 550 N, 550 N Which of the following statements is true for a body in equilibrium under the action of three concurrent forces F 1, F 2, and F 3 ? The resultant of any two forces must be equal and opposite to the third force. The forces must be mutually perpendicular. The sum of the magnitudes of the forces must be zero. The forces must act in the same direction. A balloon with mass 'm' is descending down with an acceleration 'a' (where a < g ). How much mass should be removed from it so that it starts moving up with an acceleration 'a' ? 2ma g+a 2ma g-a ma g+a ma g-a A block of mass m is placed on a smooth inclined wedge ABC of inclination θ as shown in the figure. The wedge is given an acceleration 'a' towards the right. The relation between a and θ for the block to remain stationary on the wedge is a = g a = g a = g cosec a = g A man of mass M stands on a boat of mass m at rest in still water. If the man walks a distance L on the boat towards the shore, the boat moves away from the shore by a distance: ML / (M + m) mL / (M + m) ML / m L A frictionless circular wire of unit radius is fixed on the horizontal plane. Two-point particles of unit mass start moving simultaneously from point A ( = 2 ) with identical uniform angular speeds in opposite directions, and meet again at point B ( =- 2 ) . During this time, which of the following figures schematically represent the magnitude of the total linear momentum P of the system, as a function of ? Graph (1) Graph (2) Graph (3) Graph (4) A block of mass m is sliding down a smooth inclined plane of inclination . The normal reaction is: mg mg mg mg Which of the following laws of physics is valid in all inertial frames of reference? Newton's laws of motion Coulomb's law Ohm's law Faraday's law If the earth stops rotating about its axis, the value of 'g' at the equator will: increase decrease remain same become zero A mass m is attached to a string of length L and is whirled in a horizontal circle with a constant angular velocity . If the string is suddenly cut, the mass will: Move tangentially to the circle Move radially outwards Move radially inwards Fall vertically downwards immediately Which of the following remains constant for a projectile fired from the earth, in the absence of air resistance? Horizontal component of velocity Vertical component of velocity Kinetic energy Momentum A force F is applied to a block of mass m to keep it against a vertical wall. If the coefficient of static friction is s , the minimum force F required to prevent the block from falling is mg/ s . The direction of the force F is: Horizontal Vertical upward Vertical downward At an angle to the wall A man of mass 80 kg stands on a weighing scale in a lift which is falling freely. The reading of the scale will be: Zero 80 kg 160 kg 40 kg