When two springs A and B with force constants kA and kB are stretched by the same force, then the respective ratio of the work done on them is
kB : kA
kA : kB
kA : kB : 1
A.
kB : kA
We know that force applied,
F = k . x
In the first condition,
In the second condition,
On dividing Eq. (i) by Eq. (ii), we get
In elastic collision
both momentum and kinetic energy are conserved
neither momentum nor kinetic energy is conserved
only momentum is conserved
only kinetic energy is conserved
A spring stores 1 J of energy for a compression of 1 mm. The additional work to be done to compress it further by 1 mm is
1 J
2 J
3 J
4 J
A crate is pushed horizontally with 100 N across a 5 m floor. If the frictional force between the crate and the floor is 40 N, then the kinetic energy gained by the crate is
200 J
240 J
250 J
300 J
An engine pumps out water continuously through a hose with a velocity v. If m is the mass per unit length of the water jet, the rate at which the kinetic energy is imparted to water is
mv3
The position of a particle of mass 4 g, acted upon by a constant force is given by x = 4 t2, where x is in metre and t in second. The work done during the first 2 s is
128 mJ
512 mJ
576 mJ
144 mJ
The shape of the curve representing the relation between the speed and kinetic energy of a moving object is
parabola
ellipse
straight line with positive slope
straight line with negative slope