which of the following could be effectively used to reduce friction (a) water (b)petrol (c) kerosene (d) grease​

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

If an inclined plane is 5 m long and 2 m high, what is its mechanical advantage? a. 2.5 b. 3 c. 7 d. 10

The human body stores chemical energy from digested food. some of the chemical energy is converted into mechanical energy when the body moves. which statement best supported by this information