Answer:
Explanation:
Using the efficiency formula;
Efficiency = Work done by the machine (output)/work done on the machine (input) ×100%
Efficiency =w/50 ×100
90 = 100w/50
Cross multiply
90×50 = 100W
4500 = 100W
W = 4500/100
W = 45Joules
Hence the lever does 45Joules of work on its load
2) Mechanical Advantage= Load/Effort
Given
MA = 4
Load = 500N
4 = 500/Effort
Effort = 500/4
Effort =125N
Hence the effort required to lift the load is 125N
Answer:
H(max) = (v²/2g)
Explanation:
The maximum height the ball will climb will be when there is no friction at all on the surface of the hill.
Normally, the conservation of kinetic energy (specifically, the work-energy theorem) states that, the change in kinetic energy of a body between two points is equal to the work done in moving the body between the two points.
With no frictional force to do work, all of the initial kinetic emergy is used to climb to the maximum height.
ΔK.E = W
ΔK.E = (final kinetic energy) - (initial kinetic energy)
Final kinetic energy = 0 J, (since the body comes to rest at the height reached)
Initial kinetic energy = (1/2)(m)(v²)
Workdone in moving the body up to the height is done by gravity
W = - mgH
ΔK.E = W
0 - (1/2)(m)(v²) = - mgH
mgH = mv²/2
gH = v²/2
H = v²/2g.
A wave front has the form of a surface of a sphere
Answer:
a)
= 100g
b)
= 1m/s
Explanation:
mass of one sphere '
'= 300g
First final velocity of sphere= 0m/s
a) Applying the law of conservation of momentum, assuming after two spheres collide one sphere is in positive direction and the second one is in negative.
= 
As both sphere has same initial speed i,e 
Therefore,
----->eq(1)
Applying conservation of kinetic energy
+
= 
So,
=
By substituting the above in eq(1), we have
Solving for , we have
=> 300/3
= 100g
b) In conservation of momentum, speed of center of mass before collision equals after collision. As in above part, we assumed the directions that one sphere is in positive direction and the second one is in negative.
=[(2x300) - (2 x 100)]/ (300+100)
= 1m/s
the speed of the two-sphere center of mass is 1m/s
