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प्रश्न
A man climbs a slope and another walks same distance on level road. Which of the two expends more energy and why?
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उत्तर
The man moving along the slope expends more energy. It is because, while moving along the slope, he gains height and hence has extra potential energy.
संबंधित प्रश्न
How much work is done when a force of 2 N moves a body through a distance of 10 cm in the direction of force?
What happens to the work done when the dispacement of body is at right angles to the direction of force acting on it? Explain your answer.
The work done by a force acting obliquely is given by the formula : W = F cos θ ✕ s. What will happen to the work done if angle θ between the direction of force and motion of the body is increased gradually? Will it increase, decrease or remain constant.
Is power a scalar quantity?
A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).
State the energy changes which take place when A stone dropped from the top of a cliff reaches the ground after some time.
A canon ball of mass 500g is fired with a speed of 15m/s-1. Find: its momentum.
State larger units of power.
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
