Question

A puppy weighing 3 kilograms races through the dog park. if she slows from a speed of 2 meters/second to 1 meter/second, what will happen to her kinetic energy? use the kinetic energy equation.
a.her kinetic energy decreases to 1.5 j
b.her kinetic energy increases to 1.5 j
c.her kinetic energy remains unchanged
d.her kinetic energy decreases to 1 j.

Answer 1

Your answer is A. If velocity decreases, your kinetic energy would also decrease.

Answer 2

Answer:The correct answer is option (a).

Explanation:

Mass of the puppy,m = 3 kg

Kinetic energy of the puppy when it was running with speed of 2 m/s:

$K.E=\frac{1}{2}mv^2=\frac{1}{2}\times 3kg\times (2 m/s)^2=6 Joules$

Kinetic energy of the puppy when it was running with speed of 1 m/s:

$K.E'=\frac{1}{2}mv^2=\frac{1}{2}\times 3kg\times (1 m/s)^2=1.5 Joules$

When the puppy was running at the speed f 1 m/s her kinetic energy reduced to 1.5 Joules.

Hence, correct answer is option (a).