Question

A car starts from rest and reaches a speed of 25m/s in 4 seconds. What is the acceleration?

Answer 1

Answer:

a = 6.25 m/s/s

d = 50 m

Explanation:

Given:

v1 (initial velocity)= 0 m/s (cz its at rest)

v2 (final velocity)= 25 m/s

t = 4s

a = ?

d = ?

to determine  acceleration

a = (v2 - v1)/ t

= (25m/s - 0m/s)/4s

= 6.25 m/s/s

to determine distance traveled

d = 1/2(v1 + v2)t

=1/2(0m/s+25m/s)(4s)

=50 m

Answer 2

Answer:

Answer in explanation.

Explanation:

Using Equation

$v = u + at$

where v is the final velocity

u is initial velocity

a is acceleration

t is time taken

given u = 0, v = 25, t = 4,

$25 = 0 + 4a \\ 4a = 25 \\ a = 6.25 \frac{m}{ {s}^{2} }$

Now, using equation

$v {}^{2} = {u}^{2} + 2as$

where v and u remains the same, a = 6.25 and s is the distance,

$(25) {}^{2} = \: {0}^{2} + 2(6.25)s \\ 12.5s = 625 \\ s = \frac{625}{12.5} \\ s = 50m$