Answer:
60 boxes
Explanation:
The work done by lifting a single box is equal to the force applied (the weight of the box) times the displacement of the box:
Power is related to the work done by the equation:
where W is the work done and t is the time. In this problem, we are told that the power used is P=60.0 W, while the time taken is t = 1 min = 60 s, so the total work done must be
Therefore, the number of boxes that she has to lift in order to use this power is the total work divided by the work done in lifting each box:
Answer:
the answer is
Explanation:For equilibrium
Weight = Tension
mg=T
∴T=4×3.1π=12.4πN (as can be inferred from the question)
Y=
△l/l
T/A
=
1000
0.031
/20
12.4π/π(
1000
2
)
2
=
4×0.031
12.4×20×1000×(1000)
2
=2×10
12
N/m
2
Here the block has two work done on it
1. Work done by gravity
2. Work done by friction force
So here it start from height "h" and then again raise to height hA after compressing the spring
So work done by the gravity is given as
Now work done by the friction force is to be calculated by finding total path length because friction force is a non conservative force and its work depends on total path
Total work done on it
So answer will be
None of these
<h2>
Horizontal component of the rock’s velocity when it strikes the ground is 17.25 m/s</h2>
Explanation:
In horizontal direction there is no acceleration or deceleration for a rock projected at an initial angle of 37° off the ground.
So the horizontal component of velocity always remains the same.
Horizontal component of velocity is the cosine component of velocity.
Initial velocity, u = 21.6 m/s
Angle, θ = 37°
Horizontal component of velocity = u cosθ
Horizontal component of velocity = 21.6 cos37
Horizontal component of velocity = 17.25 m/s
Since the horizontal velocity is unaffected, we have
Horizontal component of the rock’s velocity when it strikes the ground = 17.25 m/s
Answer:
I think it might be 8kg grams because it is bigger
