Last seen: Jan 25, 2021
When a freely falling body eventually stops on reaching the ground, its kinetic energy appears in the form of : heat, the body and the ground beco...
Power of each device = 500 W Number of devices = 4 Duration of use = 10 h Total energy consumed = 4 × 500 W × 10 h = 20000 Wh = 20 kW h
The acceleration of an object can be zero even if several forces are acting on it provided the resultant force (F) is zero. As F = 0, ma = 0 and accor...
1. Here, the force acts at right angle to the displacement. So, work done by the force = 0 2. Here, the direction of displacement is the same as tha...
Here, mass of the car, m = 1500 kg Initial velocity of the car, u = 60 km h-1 = = Initial kinetic energy of the car, = = 208333.3 J Fina...
Initial kinetic energy of the object, When the object comes to rest, final kinetic energy of the object, Change in kinetic energy = = Wo...
A small metallic ball (called bob) suspended by a light string (thread) from a frictionless, rigid support is called a simple pendulum. A simple pendu...
Here, power of the electric heater, P = 1500 W Time for which it is used, t = 10 h Energy used by the electric heater, i.e., W = P x t = 1500 W x 10...
The person holding a bundle of hay on his head gets tired as he experiences muscular fatigue. This fatigue is due to the conversion of chemical energy...
Yes. In the absence of any force on the object, i.e. F = 0, ma = 0 (∵ F = ma). Since m ≠ 0, a = 0. In such a case, the object is either at rest or in ...
When a satellite moves around the earth, its displacement in a short interval is along the tangent to the circular path of the satellite. The gravitat...
Potential energy of the object = m x g x h = 40 kg x 10 ms-2 x 5 m = 40 x 10 x 5 kg m s-2 = 2000 J Let v be the velocity of the object at half t...
Energy consumed = 250 units = 250 kW h = 250 × 1000 W h = 250 × (1000 W) (3600 s) = 250 × 1000 × 3600 W s = 900 × 106 = 9 × 108 J
No transfer of energy takes place when we push a huge rock unsuccessfully. The energy is spent for the physical activity of muscles.
The muscular energy of the cyclist is converted into kinetic energy (rotational) of the pedals of the bicycle which is transferred to its wheels. The ...
As the potential energy of the freely falling object decreases’, its kinetic energy increases on account of an increase in its velocity. The sum total...
Here, the mass of 10 kg is moved horizontally from point A to B. The force of gravity acts vertically downwards. Thus, the mass moves in a direction a...
Mass of the object, m = 20 kg Total work done by the force = Change in the kinetic energy of the object = = = = 10 kg x = = -210 J The ...
A battery converts chemical energy into electrical energy. This electrical energy is converted into light energy as the bulb is lighted up. The seq...
Since initial and the final positions of the path of the object thrown at a certain angle to the ground lie on the same horizontal plane, the displace...