A block of mass `1 kg` moves towards a spring of force constant `10 N//m`. The spring is massless and unstretched. The coeffcient of friction between block and surface is `0.30`. After compressing the spring, block does not return back : `(g = 10 m//s)`.A. the maximum value of speed of block for which it is possible is `3.8 m//s`B. the maximum value of speed of block of which it is possible is `4.2 m//s`C. if `E_(i)` and `E_(f)` are initial and final mechanical energy, which is sum of kinetic energy and potential energy, than work done by friction on a system is `(E_(i) - E_(f))`.D. statement in option `( C)` is wrong.

A block of mass `1 kg` moves towards a spring of force constant `10 N/

1.	A block of mass `1 kg` moves towards a spring of force constant `10 N//m`. The spring is massless and unstretched. The coeffcient of friction between block and surface is `0.30`. After compressing the spring, block does not return back : `(g = 10 m//s)`.A. the maximum value of speed of block for which it is possible is `3.8 m//s`B. the maximum value of speed of block of which it is possible is `4.2 m//s`C. if `E_(i)` and `E_(f)` are initial and final mechanical energy, which is sum of kinetic energy and potential energy, than work done by friction on a system is `(E_(i) - E_(f))`.D. statement in option `( C)` is wrong.
Answer» Correct Answer - A::C The spring is compressed by `x` Block will not return if `mu mg ge Kx` So, `x_(max) = (mu mg)/(K) =((0.3)(1)(10))/(10) =0.30 m` work done against friction `= E_(i) - E_(f)` `mu mg(x+2)=(1)/(2) mv_(0)^(2) -(1)/(2) Kx^(2)` `(0.3)(1)(10)(0.3+2)=((1)/(2))(1) v_(0)^(2) -((1)/(2))(10)(0.3)^(2)` on solving, `v_(0) = 3.8 m//sec`.

Discussion

No Comment Found

Related InterviewSolutions

A body is allowed to slide down a frictionless track from rest position at its top under gravity. The track ends in a circular loop of diameter `D`. Then, the minimum height of the inclined track (in terms of `D`) so that it may complete successfully the loop isA. `7D//4`B. `9D//4`C. `5D//4`D. `3D//4`
A body of mass `2 kg` is projected with an initial velocity of `5 ms^(-1)` along a rough horizontal table. The work done on the body by the frictional forces before it is brought to rest isA. 250 JB. 25 JC. `-250 J`D. `-25 J`
A particle is projected along a horizontal field whose coefficient of friction varies as `mu=A//r^2`, where r is the distance from the origin in meters and A is a positive constant. The initial distance of the particle is `1m` from the origin and its velocity is radially outwards. The minimum initial velocity at this point so the particle never stops isA. `infty`B. `2 sqrt(gA)`C. `sqrt(2 gA)`D. `4 sqrt(gA)`
A particle of mass `m` is projected at an angle `alpha` to the horizontal with an initial velocity `u`. The work done by gravity during the time it reaches its highest point isA. `u^(2) sin^(2) alpha`B. `(m u^(2) cos^(2) alpha)/(2)`C. `(m u^(2) sin^(2) alpha)/(2)`D. ` - (m u^(2) sin^(2) alpha)/(2)`
A car, moving with a speed of `50 km//hr`, can be stopped by brakes after at least `6 m`. If the same car is moving at a speed of `100 km//hr`, the minimum stopping distance isA. 6 mB. 2 mC. 18 mD. 24 m
A particle is projected at `t = 0` from a point on the ground with certain velocity at an angle with the horizontal. The power gravitational force is plotted against time. Which of the following is the best representation ?A. B. C. D.
A body is moved along a straight line by a machine delivering constant power . The distance moved by the body is time `t` is proptional toA. `t^(1//2)`B. `t^(3//4)`C. `t^(3//2)`D. `t^(1//4)`
A ball is thrown vertically upwards from the ground. Work done by air resistance during its time of flight isA. positive during ascent and negative during descentB. positive during ascent and descentC. negative during ascent and positive during descentD. negative during ascent and descent
A particle of mass `100 g` is thrown vertically upwards with a speed of `5 m//s`. The work done by the force of gravity during the time the particle goes up isA. `-0.5 J`B. `-1.25 J`C. `1.25 J`D. `0.5 J`
In the pulley-block system shown in figure, strings are light. Pulleys are massless and smooth. System is released from rest. In `0.3` seconds. . (a) work done on `2 kg` block by gravity is `6 J` (b) work done one `2 kg` block by string is `-2 J` ( c) work done on `1 kg` block by gravity is `-1.5 J` (d) work done on `1 kg` block string is `2 J`.A. only `a,d` are correctB. only `b,d` are correctC. only `a,b,c` are correctD. All are correct

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment