Answer:
The work done required on the coin during the displacement is 21.75 w.
Explanation:
Given that,
A coin slides over a friction-less plane i.e friction force = 0.
The co-ordinate of the given point is (1.40 m, 7.20 m).
The position vector of the given point is represented by .
The displacement of the coin is
The force has magnitude 4.50 N and its makes an angle 128° with positive x axis.
Then x component of the force = 4.50 cos128°
The y component of the force = 4.50 sin128°
Then the position vector of the force is
We know that,
work done is a scalar product of force and displacement.
=(-2.77×1.40+ 3.56×7.20) w
=21.75 w
The work done required on the coin during the displacement is 21.75 w.
B. The Earth radiates an amount of energy into space equal to the amount it receives.
Part of the solar energy is reflected by the Earth into space, this is known as albedo. The other part of the energy radiated by the Earth in the form of infrared radiation, is absorbed by the greenhouse gases, which cause most of this infrared radiation to be emitted into space. Therefore, the net flow of energy is zero.
False. Heat radiation from the sun cannot reach Earth, we cannot receive TV or GPS signals from satellites, and we cannot detect the light from distant stars.
Oh, wait . . .
Answer:
1.63103 seconds
Explanation:
= Actual period of clock = 1 second
v = Speed at which the observer is moving = 0.79 c
c = Speed of light =
Time dilation is given by
The period is 1.63103 seconds
Softer cars will crumple better in a collision- they absorb more of the impact force and therefore are safer