Question

A 8000kg engine pulls a train of 5 wagons, each of 2000kg along a horizontal track. If the engine exerts a force of 40000N and the track offers a friction force of 5000N, then calculate
a) the net accelerating force
b) the acceleration of the train​

Answer 1

▶ Solution :

Given :

▪ Mass of engine = 8000kg

▪ Mass of each wagon = 2000kg

▪ No. of wagons = 5

▪ Force exerts by engine = 40000N

▪ Frictional force against motion = 5000N

To Find :

▪ Net force exerts by engine.

▪ Net acceleration of the train.

Concept :

✒ This question is completely based on concept of newton's second law of motion.

✒ As per this law, net force on the object is defined as the product of mass and acceleration of object.

Mathematically,

☞ Fnet = m × a

• Fnet denotes net force
• m denotes mass
• a denotes acceleration

Calculation :

____________________________

✒ M = M1 + M2

• M denotes mass of train
• M1 denotes mass of engine
• M2 denotes mass of wagons

✒ M = 8000 + 5(2000)

✒ M = 8000 + 10000

✒ M = 18000kg

____________________________

✴ Net accelerating force :

→ Fnet = Fengine - Ffrictional

→ Fnet = 40000 - 5000

→ Fnet = 35000N

____________________________

✴ Net acceleration of train :

→ Fnet = M × a

→ 35000 = 18000 × a

→ a = 35/18

→ a = 1.94m/s^2