# I need Physics help with speed I will give the best answer!?

An antelope moving with constant acceleration covers the distance 69.0

m

between two points in time 7.10 s

. Its speed as it passes the second point is 15.3

m/s

What is the antelopes speed at the first point?

### 1 Answer

- 1 year agoFavorite Answer
Do you know about the SUVAT equations?

If acceleration is constant, one of the SUVAT equations is as follows:

s = 0.5*(u+v)*t, ... where

s = distance (m)

u = initial velocity (m/s)

v = final velocity (m/s)

t = time taken (between initial and final velocity) (s)...

In this case:

s = 69.0 m

u = UNKNOWN

v = 15.3 m/s

t = 7.10 s

and arrange the equation for the unknown u:

0.5*(u+v)*t = s

(u + v)t = 2s

(u + v) = (2s)/t

u = (2s)/t - v

then substitute in the values:

u = (2s)/t - v

u = (2*69)/7.1 - 15.3

u = 4.1366197

u ≈ 4.14 m/s (to 3sf - 3 significant figures just like all the values in the question.)

Therefore the antelope's initial speed was 4.14 m/s to 3sf.

- Login to reply the answers