Which of the following is/are not always necessary to observe a shadow?
Question 4
(a) Sun
(b) Screen
(c) Source of light
(d) Opaque object
Q66) Consider the following statements.
i) Force acting on a unit area of a surface is called impulse.
ii) Friction always acts against the applied force.
iii) For a force to act on an object, it is not necessary to have contact with the object.
Which of the above statements are true?