Advertisements
Advertisements
प्रश्न
A truck of mass 1000 kg, increases its speed from 36 km h-1 to 72 km h-1. Find the increase is its kinetic energy.
उत्तर
Mass (m) = 1000 kg
1 km h−1 = `5/18` ms−1
Initial speed u = `36 "km" "h"^-1 = 36 × 5/18 = 10 "ms"^-1`
Final speed v = `72 "km" "h"^-1 = 72 ×5/18 = 20 "ms"^-1`
Increase in kinetic energy = ?
Increase in kinetic energy = `1/2 mv^2 − 1/2 m u^2`
= `1/2 m [(v + u ) (v-u)]`
= `1/2 × 1000 ( 20 + 10 ) ( 20 − 10 )`
= `1/2 × 1000 × 30 × 10`
Increase in kinetic energy = 150000 J = 1.5 × `10^5` J
APPEARS IN
संबंधित प्रश्न
The energy stored in water of a dam is the kinetic energy.
The potential energy of a body is due to its state of ................... and kinetic energy of body is due to its ...............
Give one example of a body that has potential energy, in each of the following:
- due to its position at a height.
- due to its elongated stretched state.
Name the form of energy stored in a wound up spring of a watch.
Can a body possess energy even when it is not in motion? Explain your answer with an example.
Name the type of energy (kinetic or potential) possessed by the following A compressed spring.
Name the type of energy (kinetic or potential) possessed by the following A stretched rubber band.
Give an example to show the conversion of potential energy to kinetic energy when put in use.
Give reasons for the following Hammer drives a nail into the wood only when it is lifted up and then struck.
The potential energy of a body of mass 0.5 kg increases by 100 J when it is taken to the top of a tower from ground. If force of gravity on 1 kg is 10 N, what is the height of the tower?
