Kinetic
energy is the energy that is possessed by an object that is moving. It is
calculated by one-half the product of the mass and the square of the velocity
of the object. We calculate as follows:<span>
For the truck,
KE = mv^2 / 2
KE = 20000 kg (110 km/h (1 h/3600 s)(1000 m / 1 km))^2 / 2
KE = 611111.11 J
For the astronaut,
KE = 80.0 kg (27500 km/h</span>(1 h/3600 s)(1000 m / 1 km)<span>)^2/2
KE = 611111.11 J
The kinetic energy possessed by the two bodies are the same.
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The concave lens is a diverging lens, because it causes the light rays to bend away (diverge) from its axis. In this case, the lens has been shaped so that all light rays entering it parallel to its axis appear to originate from the same point, F, defined to be the focal point of a diverging lens.
#1
for the block of mass 5 kg normal force is given as


friction force is given as


Net force is given as


now we know that



#2
Normal force is given as



now we know that


as object moves with constant velocity

now for coefficient of friction we can use



#3
net force upwards is given as

mass is given as

now as per newton's law we can say



#4
As we know that when block is sliding on rough surface
part a)
net force = applied force - frictional force




part b)
for coefficient of friction we can use


here normal force is given as

now we have

#5
if an object is initially at rest and moves 20 m in 5 s
so we can use kinematics to find out the acceleration



now net force is given as


#6
an object travelling with speed 25 m/s comes to stop in 1.5 s
so here acceleration of object is given as


now the force is gievn as


Momentum = (mass) x (speed)
Mass is constant, so the rate of change of momentum is
(mass) x (rate of change of speed) .
But (rate of change of speed ) is just acceleration.
So the rate of change of momentum is (mass) x (acceleration).
But (mass) x (acceleration) is Force.
So Force is the rate of change of momentum. Verrrrrrrry interesting !
In this problem, Force = (40 kg) x (9 m/s²) = 360 newtons.
One 'Newton' is one kilogram-meter per second² .
Unit of momentum is (kilogram)-(meter per second), so 'newton'
is also a unit of time rate of change of momentum.
Rate of change of momentum is 360 momentum units per second.
Those are in a solid state.