A rope \(1\) cm in diameter breaks if the tension in it exceeds \(500\) N. The maximum tension that may be given to a similar rope of diameter \(2\) cm is:
1. \(500\) N
2. \(250\) N
3. \(1000\) N
4. \(2000\) N
The breaking stress of a wire depends on:
1. | material of the wire |
2. | length of the wire |
3. | radius of the wire |
4. | shape of the cross-section |
1. | \(10\) kg | 2. | \(20\) kg |
3. | \(40\) kg | 4. | \(80\) kg |
Two wires \(A\) and \(B\) are made of the same material. The wire \(A\) has a length \(L\) and diameter \(r\) while the wire \(B\) has a length \(2L\) and diameter \(r/2.\) If the two wires are stretched by the same force, the elongation in \(A\) divided by the elongation in \(B\) is:
1. | \(\dfrac{1}{8}\) | 2. | \(\dfrac{1}{4}\) |
3. | \(4\) | 4. | \(8\) |
A wire elongates by \(1.0\) mm when a load \(W\) is hang from it. If this wire goes over a pulley and two weights \(W\) each are hung at the two ends, the elongation of the wire will be:
1. \(0.5\) m
2. \(1.0\) mm
3. \(2.0\) mm
4. \(4.0\) mm
A heavy uniform rod is hanging vertically from a fixed support. It is stretched by its own weight. The diameter of the rod is:
1. | smallest at the top and gradually increases down the rod. |
2. | largest at the top and gradually decreases down the rod. |
3. | uniform everywhere. |
4. | maximum in the middle. |
When a metal wire is stretched by a load, the fractional change in its volume \(\frac{\Delta V}{V}\) is proportional to:
1. \(\frac{\Delta l}{l}\)
2. \(\left(\frac{\Delta l}{l}\right)^{2}\)
3. \(\sqrt{\Delta l/ l}\)
4. none of these
The length of a metal wire is \(l_1\) when the tension in it is \(T_1\) and is \(l_2\) when the tension is \(T_2.\) The natural length of the wire is:
1. \(\frac{l_{1}+l_{2}}{2}\)
2. \(\sqrt{l_{1} l_{2}}\)
3. \(\frac{l_{1} T_{2}-l_{2} T_{1}}{T_{2}-T_{1}}\)
4. \(\frac{l_{1} T_{2}+l_{2} T_{1}}{T_{2}+T_{1}}\)
A heavy mass is attached to a thin wire and is whirled in a vertical circle. The wire is most likely to break:
1. | when the mass is at the highest point |
2. | when the mass is at the lowest point |
3. | when the wire is horizontal |
4. | at an angle of \(\cos^{-1}(\frac{1}{3})\) from the upward vertical |
When a metal wire elongates by hanging a load on it, the gravitational potential energy is decreased.
1. | This energy completely appears as the increased kinetic energy of the block |
2. | This energy completely appears as the increased elastic potential energy of the wire |
3. | This energy completely appears as heat |
4. | None of these |