Systems of Particles and Rotational Motion — Physics STD 11 Science — Question

Write an expression for the work done in rotator motion.

Springs of steel and copper of equal size are stretched till equal increases in length. On which more work would have to be done?

A rectangular brick is kept on a table with a part of its length projecting out. It remains at rest if the length projected is slightly less than half the total length but it falls down if the length projected is slightly more than half the total length. Give reason.

When several passengers are standing in a moving bus, it is said to be dangerous. How will you justify this statement?

When a body is weighed on an ordinary balance we demand that the arm should be horizontal if the weights on the two pans are equal. Suppose equal weights are put on the two pans, the arm is kept at an angle with the horizontal and released. Is the torque of the two weights about the middle point (point of support) zero? Is the total torque zero? If so, why does the arm rotate and finally become horizontal?

Why should the difference between the frequencies be less than 10 to produce beats?

What would happen if gravity suddenly disappears?

When a bottle of cold carbonated drink is opened, a slight fog is formed around the opening, why?