an engine of mass 3000kg pulls teo logs of mass 800kg each with acceleration 0.2m/s². calculate the force experience by each log.
CHAPTER- FORCE AND LAW OF MOTION OR GRAVITATION
Answers
Explanation:
Step 1: FBD
F=40000N
friction =5000N
Step 2: Newton’s Second Law (a)
Applying Newton's second law on the system, (Taking rightward as positive)
∑F
net
=ma
From above figure, [Refer Fig. 1]
F
net
=F−friction
=40000−5000
=35000 N
Step 2: (b) Acceleration
According to Newton's II
nd
law, we can write:
F
net
= (Total mass) × (Acceleration)
⇒35000=(M+5m).a
⇒a=(
M+5m
35000
)
Putting given values
a=(
8000kg+(5×2000kg)
35000N
)=1.944 m/s
Step 3: (c) The force of wagon 1 on wagon 2 [Refer Fig. 2]
External force is applied directly to wagon 1 only. The net force on the last four wagons is equal to the force applied by wagon 2 by wagon 1.
Let the acceleration of the wagons be a
′
⇒ 35000=(5m)a
′
⟹35000=10000×a
′
Acceleration of the wagons a
′
=3.5 ms
−2
Mass of last 4 wagons m
′
=4×2000 kg
∴ Net force on last 4 wagons T=8000×3.5 =28000 N
Thus force on wagon 2 by wagon 1 is 28000N.