Question

5. 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 (Hint: 1 tonne = 1000 kg.)​

Answer 1

Answer:

Initial velocity of the truck, u=0

Distance covered by the truck, s=400 m

Time taken to cover that distance, t=20 s

Let the acceleration of the truck be  a

s=ut+  

2

1

​

at  

2

 

400=(0)20+  

2

1

​

a(20)  

2

   

a=2 m/s  

2

 

Mass of the truck    M=7 tonnes=7000 kg        (∵1 tonne=1000 kg)

F=Ma=7000×2 =14000 N    

Explanation:

Answer 2

Answer:

Here's your answer ☺️

Explanation:

$\huge \mathfrak \green{given}$

Initial velocity of truck, u = 0 m/s

Distance travelled by the truck, s = 400 m

Time taken, t = 20 s

Mass of truck, m = 7 tonnes

Convert tonne into kg

1 tonne = 1000 kg

So, 7 tonnes = 7000 kg

$\huge \red{to find}$

Force, F = ?

Acceleration, a = ?

Using second equation of motion

s = ut + ½ at²

On substituting values, we get

400 = 0 + ½ × a × (20)²

400 = 0 + ½ × a × 400

a = 800/400

a = 2 m/s²

Finding force

F = Mass × Acceleration

F = 7 ×10³ × 2

F = 14 × 10³ N

F = 14,000 N