Question

An antelopes moving with constant acceleration covers the distance between two points 70.0m apart in 7.0s. It’s speed aa it passes the second point is 15.0m/s

A.) What is it’s speed at the first point? b) What is the acceleration?

Answer 1

(a)

$$d=\dfrac{1}{2}(v_i+v_f)t,$$ $$v_i=\dfrac{2d}{t}-v_f,$$ $$v_i=\dfrac{2\cdot70\ m}{7\ s}-15\ \dfrac{m}{s}=5\ \dfrac{m}{s}.$$

(b)

$$v_f=v_i+at,$$ $$a=\dfrac{v_f-v_i}{t}=\dfrac{15\ \dfrac{m}{s}-5\ \dfrac{m}{s}}{7\ s}=1.43\ \dfrac{m}{s^2}.$$