Work done by a frictional force is

(1) Negative

(2) Positive

(3) Zero

(4) All of the above

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

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A block of mass 50 kg slides over a horizontal distance of 1 m. If the coefficient of friction between their surfaces is 0.2, then work done against friction is

(1) 98 J

(2) 72J

(3) 56 J

(4) 34 J

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A body of mass m is moving in a circle of radius r with a constant speed v. The force on the body is $\frac{m{v}^{2}}{r}$ and is directed towards the centre. What is the work done by this force in moving the body over half the circumference of the circle

(1) $\frac{m{v}^{2}}{\pi {r}^{2}}$

(2) Zero

(3) $\frac{m{v}^{2}}{{r}^{2}}$

(4) $\frac{\pi {r}^{2}}{m{v}^{2}}$

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A man pushes a wall and fails to displace it. He does

(1) Negative work

(2) Positive but not maximum work

(3) No work at all

(4) Maximum work

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is

(1) 0°

(2) 30°

(3) 60°

(4) 90°

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A force acts on a 30 gm particle in such a way that the position of the particle as a function of time is given by $x=3t-4{t}^{2}+{t}^{3}$, where x is in metres and t is in seconds. The work done during the first 4 seconds is

(1) 5.28 J

(2) 450 mJ

(3) 490 mJ

(4) 530 mJ

Concept Questions :-

Work done by variable force
High Yielding Test Series + Question Bank - NEET 2020

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The work done in pulling up a block of wood weighing 2 kN for a length of 10m on a smooth plane inclined at an angle of 15° with the horizontal is (given: sin15°=0.2588):

(1) 4.36 kJ

(2) 5.17 kJ

(3) 8.91 kJ

(4) 9.82 kJ

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A force $\stackrel{\to }{F}=5\stackrel{^}{i}+6\stackrel{^}{j}-4\stackrel{^}{k}$ acting on a body, produces a displacement $\stackrel{\to }{s}=6\stackrel{\to }{i}+5\stackrel{\to }{k}.$ Work done by the force is

(1) 18 units

(2) 15 units

(3) 12 units

(4) 10 units

Concept Questions :-

Concept of work
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A body of mass 6kg is under a force which causes displacement in it given by $S=\frac{{t}^{2}}{4}$ metres where t is time. The work done by the force in 2 seconds is-

(1) 12 J

(2) 9 J

(3) 6 J

(4) 3 J

Concept Questions :-

Work done by variable force
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A force of $\left(3\text{​\hspace{0.17em}}\stackrel{^}{i}+4\text{\hspace{0.17em}}\stackrel{^}{j}\right)$ Newton acts on a body and displaces it by $\left(3\text{\hspace{0.17em}}\stackrel{^}{i}+4\text{​}\stackrel{^}{j}\right)\text{\hspace{0.17em}}m.$ The work done by the force is

(1) 10 J

(2) 12 J

(3) 16 J

(4) 25 J

Concept Questions :-

Concept of work