The engine's efficiency is (35J)/125J) = 28% .
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Answer:

Explanation:
A simple pendulum is a system consisting of a mass attached to a string, and oscillating in a periodic motion, back and forth, along an equilibrium position.
The period of a pendulum is the time it takes for the pendulum to complete one oscillation.
The period of a pendulum is given by the equation

where
L is the length of the pendulum
g is the acceleration due to gravity
From the formula, we see that the period of a pendulum does not depend on the mass.
Therefore, the only 2 factors affecting the period of a pendulum are:
- The length of the pendulum: the longer it is, the longer the period of oscillation
- The acceleration due to gravity: the greater it is, the shorter the period of the pendulum
Answer:
3540.5N
Explanation:
Step one:
given data
mass m= 0.196kg
speed v= 31m/s
distance r= 5.32cm = 0.0532m
Step two
The expression relating force, mass, velocity and distance is
F= mv^2/r
substitute we have
F=0.196*31^2/0.0532
F=0.196*961/0.0532
F=188.356/0.0532
F=3540.5N
The east bound train travels at a speed of 95 mile per hour and the west bound train at 75 miles per hour.
Assuming eastbound train will cover distance x then the west bound train will cover distance 272-x .
Therefore, since time taken will be the same then; x/95 = (272-x)/75
= 75x = 95 (272-x)
= 75x = 25840 - 95x
= 170 x= 25840
x = 152 miles
Thus time taken will either be x/95 or (272-x)/75
= 152/95
= 1.6 hours or 1 hour 36 minutes