If a car doubles its velocity, the car\'s kinetic energy ___ (A) doubles (B) rem

Question

If a car doubles its velocity, the car's kinetic energy ___ (A) doubles (B) remains constant (C) triples (D) quadruples Which of the following situations requires the greatest power? (A) 10 J of work done in 2 seconds (B) 40 J of work done in 10 seconds (C) 10 J of work done in 4 seconds (D)40 J of work done in 20 seconds As an object falls down without air resistance, the object ___ (A) loses kinetic energy (B) moves with increasing momentum (C) loses potential energy (D) B and C If the distance between two masses is doubled, the gravitational force between the masses ___ (A) halves (B) quarters (C) doubles (D) stays the same How much work is done when you push a crate with a 100 N force through a distance of 10 m? (A) 200 J (B) 1000 J (C) 2000 J (D) 5 J When an ice skater pulls her outstretched arms inward, she spins --- (A) faster since her rotational inertia increases (B) faster since her rotational inertia decreases (C) slower since her rotational inertia increases (D)slower since her rotational inertia decreases A car moves in a circular path. If the car doubles its speed, the centripetal force needed to keep the car on the curve ___ (A) stays the same (B) doubles (C) quadruples (D) halves

Explanation / Answer

Q.1 ) KE = 1/2 mv^2 ( doubling velocity will result i n quadraples KE)

opotion D

Q.2 : power = work done / time

option A = 10 j/ 2 = 5 watts

Q.3 it will losses potential energy = mgh

Q. 4 F = GmM/ r^2 ( doubling ,distance will result in force becoming quarters)

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