Here
- Acceleration and initial velocities are constant.
According to first equation of kinematics.
- Time was t at velocity v
- Time will be 4t at velocity 4v
Answer:the branch of science concerned with the nature and properties of matter and energy. The subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.
Explanation:
The work done by the applied force = 650 J
Given the mass of the box = 40 kg
The displacement of the box on applying force = 5 m
Applied horizontal force = 130 N
The co-efficient of friction between box and floor is = 0.3
We have to find the work done by the applied force.
Work done by the applied force = Applied Force x Displacement of the box
= 130 N x 5 m
= 650 J
[Here the unit Nm is known as Joule(J) ]
We have the co-efficient of friction. So,
The force applied due to friction = Mass of the box x Co-efficient of friction x Acceleration due to gravity
= 40 kg x 0.3 x 9.8
= 117.6 N
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Answer:
The correct answer is option 'c': 30 AUs
Explanation:
For a spherical wave front emitted by sun with total energy 'E' the energy density over the surface when it is at a distance 'r' from the sun is given by
This energy per unit area is sensed by observer as intensity of the sun.
Let the initial intensity of sun at a distance 
be 
Thus if the sun becomes 900 times dimmer we have
Thus the distance increases 30 times.
