Because gravity pulls it down
Answer:
F = 102 N
Explanation:
ASSUMING the track is horizontal to avoid gravity potential energy considerations.
The work of the applied force must overcome friction work and increase the kinetic energy of the runner
F(d) = Ff(d) + ½m(v² - u²)
F = Ff + m(v² - u²) / 2d
F = 30.0 + 60.0(8.00² - 2.00²) / (2(25.0))
F = 102 N
Answer:
It takes
to accelerate the object from rest to the speed v.
Explanation:
From Newton's second law:
(1)
and the definition of acceleration,
(2)
we can solve this problem. Putting (2) in (1) we have:
and solving for
and considering the initial time as zero (
) and the initial velocity also zero (
) we have:

Now, for a mass
and the
we can wrtie the same equation:
and substituting
and
:

So now, it only takes half the time to accelerate the object from rest to the speed v
Answer:
Tortoise has the greatest momentum
Explanation:
Momentum of tourtise (p)=mass×velocity
=275×0.55
=151.25 kgm/s