Question

A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 tonnes
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Answer 1

hey mate here is your answer

as we know that
v=u+a t

given, distance(v,finAL velocity) =400m
time(t)=20 sec
initial velocity (u)=0

400=0 +a ×20
400/20 =a
a=20

now , mass=7 tonnes
we know that
F=ma
F=7000×20 (1 tonne=1000kg)
F=140000

Answer 2

✬ Acceleration = 2 m/s² ✬

✬ Force = 14000 N ✬

Explanation:

Given:

• Distance (S) is 400 m
• Initial speed (u) is 0 ( Truck starts from rest )
• Time (T) is 20 s.
• Mass of truck is 7 tonnes.

To Find:

• What is the acceleration (a) ?
• What is the force (F) ?

Solution: To find acceleration we use the formula

★ S = ut + 1/2 at² ★

• Putting all the values in formula

$\small\implies{\sf }$ 400 = ( 0 x 20 ) + 1/2 (a) (20)²

$\small\implies{\sf }$ 400 = 0 + 1/2 (a) x 400

$\small\implies{\sf }$ 400 = 200a

$\small\implies{\sf }$ 400/200 = a

$\small\implies{\sf }$ 2 m/s² = a

Hence, The acceleration is 2 m/s².

• To calculate force we use the formula •

★ Force (F) = Mass (m) x Acceleration (a) ★

• Putting all the values in formula

→ 1 tonne = 1000 kg

∴ 7 tonne = 7 x 1000 = 7000 kg

$\small\implies{\sf }$ F = 7000 x a

$\small\implies{\sf }$ F = 7000 x 2

$\small\implies{\sf }$ F = 14000 N

Hence, The force is 14000 Newtons.