Question

There are three objects in the following scenarios : (i) a 100-kg football linebacker running at 10 m/s; (ii) a 1 kg ball rolled on the ground at 10 m/s; (iii) a 1000 kg boat moving at 1 m/s. Put the objects in order of the least to the most kinetic energy.

(b) In a freak turn of events, you will be hit by one of these objects. To minimize the damage to yourself, which object would you prefer to be hit by?

(c) Do any of these objects have more gravitational potential energy than the others?

Answer 1

(a)

formula for kinetic energy

KE = 1/2 * mv^2

KE for football

KE = 1/2 * 100(10)^2 = 5000 J

KE for ball

KE = 1/2 * 1 (10)^2 = 50 J

KE for boat

KE = 1/2 * (1000) ( 1)^2 = 500 J

(b)

to minimize damage we use small kinetic energy of the object, from the above three objects , ball is prefer to minimize damage

(c)

formula for gravitational potential energy

PE = mgh

gravitational potential energy depends on , mass and height of the object, height of the objects are not given in the problem, so we cannot determine gravitational potential energy.

if all objects have same height than higher mass object have more gravitational potential energy than the others, then

Boat has more gravitational potential energy .