Question

You travel from point A to point B in a car moving at a constant speed of 70 km/h. Then you travel the same distance from point B to another point C, moving at a constant speed of 90 km/h. Is your average speed for the entire trip from A to C equal to 80 km/h? Explain why or why not.

Answer 1

Answer:

Yes, the average speed for the entire trip from A to C is equal to $80\frac{km}{h}$

Step-by-step explanation:

The average speed of an object is defined as the distance traveled divided by the time elapsed. Velocity is a vector quantity, and average velocity can be defined as the displacement divided by the time. For the special case of straight line motion in the x direction, the average velocity takes the form:

$V_a_v_e_r_a_g_e=\frac{x_2-x_1}{t_2-t_1}=\frac{Δx}{Δt}$

If the beginning and ending velocities for the motion are known, and the acceleration is constant, the average velocity can also be expressed as:

$V_a_v_e_r_a_g_e=\frac{V_1+V_2}{2}$

We Know that:

$V_1=70\frac{km}{h} \\\\V_2=90\frac{km}{h}$

Replacing the values:

$V_a_v_e_r_a_g_e=\frac{70+90}{2} =\frac{160}{2}=80\frac{km}{h}$