High School

A child on a tricycle has a total mass of 42 kg and is moving at a speed of 3 m/s. What is the kinetic energy of the child/tricycle in SI units?

a) 63 J
b) 378 J
c) 189 J
d) 126 J

Answer :

Final answer:

The kinetic energy of the child/tricycle system, with a mass of 42 kg and a speed of 3 m/s, is calculated as 189 J using the kinetic energy formula.

Explanation:

The kinetic energy of a child and tricycle system. Kinetic energy can be found using the formula KE = 1/2 mv2, where 'm' is mass and 'v' is velocity.

In this case, the mass (m) is 42 kg, and the velocity (v) is 3 m/s.

Plugging these values into the formula:

KE = 1/2 (42 kg) (3 m/s)2,

KE = 1/2 (42 kg) (9 m2/s2),

KE = 189 J.

Therefore, the correct answer is (c) 189 J.