The thermal efficiency of an engine is
where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
Answer:
Definition - The friction that occurs when an object rolls across a rolling friction is easier to overcome than sliding friction.
Ex - Anything with wheels (cars, bicycle,etc) or ball rolling.
Explanation:
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Answer:
12.68 m/s.
Explanation:
Equations of motion:
i. S = vi*t + 1/2 * a*(t^2)
ii. vf = vi + a*t
iii. vf^2 = vi^2 + 2a*S
Where, vf = final velocity
vi = initial velocity
S = distance travelled
a = acceleration due to gravity
t = time taken
Given:
vi = 0 m/s
S = 8.2 m
vf = ?
a = 9.81 m/s^2
Using iii. Equation of motion,
vf^2 = vi^2 + 2a*S
= 2 * 9.81 * 8.2
= 160.884
vf = sqrt (160.884)
= 12.68 m/s.
Answer:
System D --> System C --> System A --> System B
Explanation:
The gravitational force between two masses m1, m2 separated by a distance r is given by:
where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:
System A has masses m and m separated by a distance r:
system B has masses m and 2m separated by a distance 2r:
system C has masses 2m and 3m separated by a distance 2r:
system D has masses 4m and 5m separated by a distance 3r:
Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:
System D --> System C --> System A --> System B
Explanation:
Explanation: It's because when he stop down from a moving bus his feet come at rest while the upper portion of his body is still in motion and he falls in the forward direction.