Answer:
- The thermal efficiency is 0.4113.
Explanation:
We know that the thermal efficiency is the ratio of work done by the engine over the heat taken

Now, how much work the engine do in a cycle?
We know that the work done in a cycle must be equal to the heat taken minus the heat rejected

So, the thermal efficiency will be:



Putting the values of the problem


Answer:

Explanation:
Let m is the mass of both cars. The first car is moving with speed v and the other car is moving with speed 2v. The only force acting on both cars is the centripetal force.
For faster car on the road,

v = 2v

..........(1)
For the slower car on the road,
............(2)
Equation (1) becomes,


So, the frictional force required to keep the slower car on the road without skidding is one fourth of the faster car.
Answer:
The speed on boat in still water is
and the rate of the current is 
Explanation:
Since speed , 
Therefore speed of motor boat while traveling upstream is

and speed of motor boat while traveling downstream is
Let speed of boat in still water be
and rate of current be 
Therefore
----(A)
and
------(B)
Adding equation (A) and (B) we get

=>
------(C)
Substituting the value of
in equation (A) we get

Thus the speed on boat in still water is
and the rate of the current is 
I think that numbers one, three, and four are true
Answer:
272.89g
Explanation:
Find the diagram to the question in the attachment below;.
Using the principle of moment to solve the question which states that the sum of clockwise moment is equal to the sum of anticlockwise moment.
Moment = Force * Perpendicular distance
Taking the moment of force about the pivot.
Anticlockwise moment:
The 85g mass will move in the anticlockwise
Moment of 85g mass = 85×36.6
= 3111gcm
Clockwise moment.
The mass of the metre stick M situated at the centre (50cm from each end) will move in the clockwise direction towards the pivot.
CW moment = 11.4×M = 11.4M
Equating CW moment to the ACW moment we will have;
11.4M = 3111
M = 3111/11.4
M = 272.89g
The mass of the metre stick is 272.89g