Chapter 7 – Work, Energy and Power
Sahay Sir > Question Answers > Cengage JEE Mains Physics by B.M Sharma > Chapter 7 - Work, Energy and Power
A projectile is fired with some velocity making certain angle with the horizontal. Which of the following graphs is the best representation for the kinetic energy of a projectile (KE) versus its horizontal displacement (x)?
20
Oct
A projectile is fired with some velocity making certain angle with the horizontal. Which of the following graphs is the best representation for the kinetic energy of a projectile (KE) versus its horizontal displacement (x)? A person of mass 70kg jumps from a stationary helicopter with the parachute open. As he falls through 50 m [...]
A particle of mass m slides on a frictionless surface ABCD, starting from rest as shown in figure. The part BCD is a circular arc. If it looses contact at point P, the maximum height attained by the particle from point C is
20
Oct
A particle of mass m slides on a frictionless surface ABCD, starting from rest as shown in figure. The part BCD is a circular arc. If it looses contact at point P, the maximum height attained by the particle from point C is A particle of mass m slides on a frictionless surface ABCD starting [...]
Two identical blocks A and B are placed on two inclined planes as shown in figure. Neglect resistance and other friction. Read the following statements and choose options. Statement I: The kinetic energy of A on sliding to J will be greater than the kinetic of B on sliding to O. Statement II: The acceleration of A will be greater than acceleration of B when both are released on the inclined plane. Statement III: The work done by external agent to move the block slowly from position B to O is negative.
20
Oct
Two identical blocks A and B are placed on two inclined planes as shown in figure. Neglect resistance and other friction. Read the following statements and choose options. Statement I: The kinetic energy of A on sliding to J will be greater than the kinetic of B on sliding to O. Statement II: The acceleration [...]
A particle of mass m moves with a variable velocity v, which changes with distance covered x along a straight line as v = kx−−√, where k is a positive constant. The work done by all the forces acting on the particle, during the first t seconds is
20
Oct
A particle of mass m moves with a variable velocity v, which changes with distance covered x along a straight line as v = kx−−√, where k is a positive constant. The work done by all the forces acting on the particle, during the first t seconds is A particle of mass m moves with [...]
A person of mass 70kg jumps from a stationary helicopter with the parachute open. As he falls through 50 m height, he gains a speed of 20 ms^−1. The work done by the viscous air drag is
20
Oct
A person of mass 70kg jumps from a stationary helicopter with the parachute open. As he falls through 50 m height, he gains a speed of 20 ms^−1. The work done by the viscous air drag is A person of mass 70kg jumps from a stationary helicopter with the parachute open. As he falls through [...]
When a person stands on a weighing balance, working on the principle of Hooke’s law, it shows a reading of 60 kg after a long time and the spring gets compressed by 2.5 cm. If the person jumps on the balance from a height of 10 cm, the maximum reading of the balance will be
20
Oct
When a person stands on a weighing balance, working on the principle of Hooke’s law, it shows a reading of 60 kg after a long time and the spring gets compressed by 2.5 cm. If the person jumps on the balance from a height of 10 cm, the maximum reading of the balance will be [...]
The system shown in figure is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of spring k=40 N/m and g=10m/s^2
20
Oct
The system shown in figure is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of spring k=40 N/m and g=10m/s^2 and friction [...]
A particle is released from the top of two inclined rough surface of height h each. The angle of inclination of the two planes are 30^∘ and 60^∘ respectively. All other factors (e.g. coefficient of friction , mass of the block etc) are same in both the cases. Let K1 and K2 be the kinetic energy of the particle at the bottom of the plane in two cases. Then
20
Oct
A particle is released from the top of two inclined rough surface of height h each. The angle of inclination of the two planes are 30^∘ and 60^∘ respectively. All other factors (e.g. coefficient of friction , mass of the block etc) are same in both the cases. Let K1 and K2 be the kinetic [...]
A spring is compressed between two toy carts to masses m1 and m2. When the toy carts are released, the spring exerts on each toy cart equal and opposite forces for the same small time t. If the coefficients of friction μ between the ground and the toy carts are equal, then the magnitude of displacements of the toy carts are in the ratio
20
Oct
A spring is compressed between two toy carts to masses m1 and m2. When the toy carts are released, the spring exerts on each toy cart equal and opposite forces for the same small time t. If the coefficients of friction μ between the ground and the toy carts are equal, then the magnitude of [...]
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A spring is compressed between two toy carts to masses m1 and m2. When the toy carts are released ,
the spring exerts on each toy cart equal and opposite forces for the same small time t. If the coefficients of friction μ between the ground and the toy carts are equal ,
then the magnitude of displacements of the toy carts are in the ratio ,
A block of 4kg mass starts at rest and slides a distance d down a friction less incline ( angle 30^∘) where it runs into a spring of negligible mass. The block slides an additional 25 cm before it is brought to rest momentarily by compressing the spring. The force constant of the spring is 400Nm^−1. The value of d is (take g=10ms^−2)
20
Oct
A block of 4kg mass starts at rest and slides a distance d down a friction less incline ( angle 30^∘) where it runs into a spring of negligible mass. The block slides an additional 25 cm before it is brought to rest momentarily by compressing the spring. The force constant of the spring is [...]