Question

a 20 - kg bicycle carrying a 50 - kg girl is traveling at a speed of 8 m/s. what is the kinetic energy of the girl and bicycle together? kinetic energy is the energy that objects possess due to their motion. $ke=\frac{1}{2}mv^{2}$ m = mass (kg) v = velocity (m/s) ke = kinetic energy (j) 1600 j 280 j 2240 j 640 j

Explanation:

Step1: Calculate total mass

The mass of the bicycle is 20 - kg and the mass of the girl is 50 - kg. So the total mass $m=20 + 50=70$ kg.

Step2: Use kinetic - energy formula

The formula for kinetic energy is $KE=\frac{1}{2}mv^{2}$. Given $m = 70$ kg and $v = 8$ m/s. Substitute these values into the formula: $KE=\frac{1}{2}\times70\times8^{2}$.
First, calculate $8^{2}=64$. Then, $\frac{1}{2}\times70\times64 = 35\times64 = 2240$ J.

Answer:

2240 J