A man sharpens his knife. Which of these statements describes the properties of friction that are observed in the situation?
A. Friction helps to induce magnetism
B. Friction acts in the opposite direction of relative motion.
C. Friction causes the surfaces in contact to wear away.
D. Friction produces heat energy.
A man sharpens his knife. Which of these statements describes the properties of friction that are observed in the situation?
A. Friction helps to induce magnetism
B. Friction acts in the opposite direction of relative motion.
C. Friction causes the surfaces in contact to wear away.
D. Friction produces heat energy.
The correct option is D B,C,D
Friction is not responsible for magnetism even though we can magnetize a non-magnetic substance by rubbing it with a magnet. It is the magnetic field that causes this phenomenon. Friction always opposes relative motion between surfaces. A knife can be sharpened by rubbing it to another irregular surface. While rubbing the irregular surfaces interlock with each other causing wear and tear of surfaces. To overcome friction we needs to break the bonds formed between two surfaces. When bonds are broken atoms start to vibrate thereby increasing temperature. (Temperature is nothing but the average kinetic energy of all particles). Hence, all other options are correct apart from option A.
B,C,D
Friction is not responsible for magnetism even though we can magnetize a non-magnetic substance by rubbing it with a magnet. It is the magnetic field that causes this phenomenon. Friction always opposes relative motion between surfaces. A knife can be sharpened by rubbing it to another irregular surface. While rubbing the irregular surfaces interlock with each other causing wear and tear of surfaces. To overcome friction we needs to break the bonds formed between two surfaces. When bonds are broken atoms start to vibrate thereby increasing temperature. (Temperature is nothing but the average kinetic energy of all particles). Hence, all other options are correct apart from option A.
