# Question b7a84

Dec 2, 2015

$F = 480 N$

#### Explanation:

The special case of Newton's second law of motion relates resultant force and acceleration:
$F = m a$

The question specifies that the acceleration is uniform, so we can use the equations of uniform acceleration to determine the value of $a$ for $F = m a$

Stage 1: Determine which "suvat" equation to use.
List all values we know:
$s : 32 m$
$u : 0 m {s}^{- 1}$
v: × 
a:?
$t : 12.0 s$

So we need.to use the equation that does not have $v$ in it, i.e. s=ut +½ at^2

Rearrange for the unknown, $a$ (u=0 so ut=0), and substitute cakes into the equation.
s=½ at^2 ⇒ a=2s/t^2=(2 × 32) / 12^2 = 0.4444 m s^(-2)

Stage 2 : Use that acceleration to calculate the force.
The mass of the pachyderm is given as 1080 kg.
F=ma=1080×0.4444= 479.952 N #

To 3 s.f that is $F = 480 N$