The mechanical advantage is defined as the ratio between the force produced by a machine and the force applied in input:

For the crowbar of the problem, the force applied in input is 40 N, while the force produced in output is equal to the weight of the rock that is lifted, so 400 N. Therefore, the mechanical advantage is
Answer:
Explanation:
We shall apply Pascal's Law in fluid mechanics
According to it , pressure is transmitted in liquid from one point to another without any change .
25 cm diameter = 12.5 x 10⁻² m radius
Area = 3.14 x (12.5 x 10⁻²)²
= 490.625 x 10⁻⁴ m²
Pressure by vehicle
Force / area
13000 / 490.625 x 10⁻⁴
= 26.497 x 10⁴ Pa
5 cm diameter = 2.5 x 10⁻² radius
area = 3.14 x (2.5 x 10⁻²)²
= 19.625 x 10⁻⁴ m²
If we assume required force F on this area
Pressure = F / 19.625 x 10⁻⁴ Pa
According to Pascal Law
F / 19.625 x 10⁻⁴ = 26.497 x 10⁴
F = 19.625 x 26.497
= 520 N
Answer:

Explanation:
As we know by force equation that force along the inclined planed due to gravity is given as

so the acceleration due to gravity along the plane is given as

now we have



now we know that



Answer:
B. QC > 0; QH < 0
Explanation:
Given that there are two reservoir of energy.
Sign convention for heat and work :
1.If the heat is adding to the system then it is taken as positive and if heat is going out from the system then it is taken as negative.
2. If the work is done on the system then it is taken as negative and if the work is done by the system then it is taken as positive.
From hot reservoir heat is going out that is why it is taken as negative

From cold reservoir heat is coming inside the reservoir that is why it is taken as positive

That is why the answer will be
,