Acceleration= v/ r
So you have to divide 700 by 0.800 which is equal to 875 m/s 2
He rode his bike 0.4 miles because you divide 20 by 50
K=?
M=100kg
V=10.0km/s. (100)*(10.0^2)
K=_____________
2
(100)*(100)
________
2
10,000m/s^2
_______
2
5000j
Work done = 0.5*m*[(v2)^2 - (v1)^2]
where m is mass,
v2 and v1 are the velocities.
Given that m = 1.50 x 10^3 kg, v2 = -15 m/s (decelerates), v1 = 25 kg,
Work done = 0.5 * 1.50 x 10^3 * ((-15)^2 - 25^2) = 3 x 10^5 joules
Just ignore the negative value for the final result because work is a scalar quantity.
