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? the si unit for energy is —. options: kilogram, joules, calorie, meters per second the kinetic energy of an object increases as its — increases. options: specific heat, gravitational energy, potential energy, velocity

Explanation:

Step1: Recall kinetic - energy formula

The formula for kinetic energy is $K = \frac{1}{2}mv^{2}$, where $m$ is the mass and $v$ is the velocity.

Step2: Calculate total mass

The mass of the bicycle is $m_1=20$ kg and the mass of the girl is $m_2 = 50$ kg. So the total mass $m=m_1 + m_2=20 + 50=70$ kg.

Step3: Substitute values into formula

Given $v = 8$ m/s and $m = 70$ kg, we have $K=\frac{1}{2}\times70\times8^{2}$.
First, calculate $8^{2}=64$. Then $\frac{1}{2}\times70\times64 = 35\times64=2240$ J.

The SI unit for energy is joules. Kinetic energy of an object increases as its velocity increases.

Answer:

The SI unit for energy is joules.
The kinetic energy of the girl and bicycle together is $2240$ J.
The kinetic energy of an object increases as its velocity increases.