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
Given that the space station is free of gravitational force, it is required that it spins an certain speed to acquire centripetal acceleration.
In this case, you want that the centripetal acceleration, Ac, equals g (gravitational acceleration on the earth), becasue this will cause a centripetal force equal to the weight on earth.
The formula for centripetal acceleration is Ac = [angular velocity]^2*R
where R = [1/2]50.0m = 25.0 m
Ac = 9.81 m/s^2
=> [angular velocity]^2 = Ac/R = 9.81m/s^2v/ 25.0m = 0.3924 (rad/s)^2
[angular velocity] = √(0.3924) rad/s = 0.63 rad/s
Answer: 0.63 rad/s
The last 2. They both are correct. I hope this helps.
The answer is -17x-1. You have to combine like terms.
Error is the difference between the true value of the measurand and the measured value.. Uncertainty characterizes the range of values within which the true value is asserted to lie with some level of confidence.
If that doesn’t help here’s the definition of both the terms,
Error:
A mistake
Uncertainty:
the state of being uncertain.
