Answer:
3.6 m/s
Explanation:
From the law of conservation of momentum,
Total momentum before jump = Total momentum after jump
<em>Note: Before Dan jump off the skateboard, they where both moving with the same velocity</em>
u(m+m') = mv+m'v'................. Equation 1
Where m = Dan's mass, m' = mass of the skateboard, u = common velocity before the jump, v = Dan's final velocity, v' = The final velocity of the skateboard.
make v the subject of the equation
v = [u(m+m')-m'v')]/m.............. Equation 2
Given: u = 4.0 m/s, m = 50 kg, m' = 5 kg, v' = 8 m/s
Substitute into equation 2
v = [4(50+5)-(5×8)]/50
v = (220-40)/50
v = 180/50
v = 3.6 m/s
The correct answer is B. hopes this help
The distance to a lightning bolt can be determined by counting the seconds between the flash and the sound of thunder due to the speed of light is greater than the speed of sound
We must consider that the speed of light (3.00× 10⁸ m/s) is greater than the speed of sound (340 m/s), this is why we can first see the lightning and after seeing it we can hear it.
In order to calculate the distance we must count the time since the lightning bolt and use the speed of sound, applying the following formula:
x = v * t
Where:
- x = distance
- t = time
- v = velocity
<h3>What is velocity?</h3>
It is a physical quantity that indicates the displacement of a mobile per unit of time, it is expressed in units of distance per time, for example (miles/h, km/h).
Learn more about velocity at: brainly.com/question/80295?source=archive
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The power of the lens is 2 diopter means that this lens has a focal length of 1/2 meter.
The focal length = 1 ÷ ( the number of diopters)
If one's glass prescription shows that the power of the lens is 2 diopter it means that the person is far-sighted. It means if a person needs to see something which is quite distant then his eyes need extra lens power to focus on it. Moreover, if there's a sign convention it means '+' indicates a convex lens and '-' concave lens. Also in-camera close up lens are also measured in terms of diopter.
I hope this answer helps.
To learn more about lenses,
brainly.com/question/766997
brainly.com/question/17014859
Answer:
Described below
Explanation:
When you see a car behind you in the rear view mirror, it means that light rays travelling from the right hand side of the car driver behind are being reflected by the mirror to get to your eyes on the right side of the light rays from the drivers left hand side.
