Answer:
He needs 1.53 seconds to stop the car.
Explanation:
Let the mass of the car is 1500 kg
Speed of the car, v = 20.5 m/s
He will not push the car with a force greater than, 
The impulse delivered to the object is given by the change in momentum as :

So, he needs 1.53 seconds to stop the car. Hence, this is the required solution.
Answer:
P = 4000 [W]
Explanation:
In order to solve this problem, we must first determine the work, which is defined as the product of force by distance.
W = F*d
where:
W = work [J] (units in Joules)
F = force = 1000[N]
d = distance = 2 [m]
W = 1000*2
W = 2000 [J]
And power is defined as the relationship between work and the time in which the work is done.
P = W/t
P = power [W] (units of watts)
t = time = 0.5 [s]
P = 2000/0.5
P = 4000 [W]
Answer:
milligrams
explanation:
kilograms are too big
<em>Hope this helps :)</em>
The magnitude of the kinetic friction force, ƒk, on an object is. Where μk is called the kinetic friction coefficient and |FN| is the magnitude of the normal force of the surface on the sliding object. The kinetic friction coefficient is entirely determined by the materials of the sliding surfaces. hope it helps
Assuming constant acceleration due to gravity of
, and assuming the passengers start at rest, so that
, we have

or 54 m/s if taking significant digits into account.