select the correct answer from each drop - down menu. use $ke=\frac{1}{2}mv^{2}$. a boy weighing drop - down…

select the correct answer from each drop - down menu. use $ke=\frac{1}{2}mv^{2}$. a boy weighing drop - down kilograms is riding a skateboard. hes moving at 2 meters/second and has 40 joules of kinetic energy. he doubles his speed when he sees his friends ahead of him. his kinetic energy at the faster speed is drop - down joules.

select the correct answer from each drop - down menu. use $ke=\frac{1}{2}mv^{2}$. a boy weighing drop - down kilograms is riding a skateboard. hes moving at 2 meters/second and has 40 joules of kinetic energy. he doubles his speed when he sees his friends ahead of him. his kinetic energy at the faster speed is drop - down joules.

Answer

Explanation:

Step1: Find the mass of the boy

We know $KE=\frac{1}{2}mv^{2}$, where $KE = 40$ J and $v = 2$ m/s. Rearranging the formula for $m$ gives $m=\frac{2KE}{v^{2}}$. Substituting the values: $m=\frac{2\times40}{2^{2}}=\frac{80}{4}=20$ kg.

Step2: Find the new kinetic - energy

The boy doubles his speed, so the new speed $v_{new}=2\times2 = 4$ m/s and $m = 20$ kg. Using the kinetic - energy formula $KE=\frac{1}{2}mv^{2}$, we have $KE=\frac{1}{2}\times20\times4^{2}=10\times16 = 160$ J.

Answer:

The boy weighs 20 kilograms and his kinetic energy at the faster speed is 160 joules.