5m/s
100m
Explanation:
Average speed is sum of distance distance traveled in a given time by a body.
Average speed=
Distance = 20m
time = 4s
Average speed = = 5m/s
For the spaceship;
Distance covered = speed x time
Speed = 50m/s
time = 2s
Distance covered = 50 x 2 = 100m
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Answer:
The focal length is 16.86 cm and the distance of the man if he wants to form an upright image of his chin that is twice the chin's actual size is 8.43 cm.
Explanation:
Given that,
Object distance u=1.54 m =154 cm
Image distance v = 15.2 cm
Magnification = 2
We need to calculate the focal length
Using formula of mirror
Put the value into the formula
We need to calculate the focal length
Using formula of magnification
Put the value into the formula
Using formula of for focal length
Hence, The focal length is 16.86 cm and the distance of the man if he wants to form an upright image of his chin that is twice the chin's actual size is 8.43 cm.
If you compare the energy at two different times in an equation, you'll see no difference, because it's been conserved. The total energy of a system is the sum of its energy in motion - its kinetic energy - and its energy due to its position, which is its potential energy