Advertisements
Advertisements
Question
A bullet fired against a window glass pane makes a hole in it without any cracks while a stone striking the same glass pane smashes it; explain with reason.
Advertisements
Solution
When the bullet strikes the glass, the part of the glass coming in contact with the bullet immediately shares the large velocity of the bullet and makes a hole in it while the rest of the glass pane, due to the inertia of rest, remains at rest and so is not smashed. But when a stone strikes the same glass pan, the surrounding part of the glass gets time to share the comparatively low velocity of stone and so it is smashed.
RELATED QUESTIONS
A boy weighing 40 kgf climbs up a stair of 30 steps each 20 cm high in 4 minutes and a girl weighing 30 kgf does the same in 3 minutes. Compare:
- The work done by them.
- The power developed by them.
Give the expression for mechanical advantage of an inclined plane in terms of the length of an inclined plane.
State the condition when the work done by a force is positive. Explain with the help of examples.
What physical quantity does the electron volt (eV) measure? How is it related to the S.I. unit of that quality?
How is kilowatt hour related to joule?
What do you mean by equilibrium of a body?
A mechanic can open a nut by applying a force of 200 N while using a lever handle of 50 cm length. How long handle is required if he wants to open it by applying a force of only 50 N?
What do you mean by uniform circular motion?
What is the work done by the gravitational force on the moon that revolves around the earth?
State the condition when the work done by the force is positive
