Aparent swings a 11.5 kg
child in a circle of radius
0.711 m, making 12 revolutions
in 27.4 s. how much force does
the parent exert on the child?
(unit = n)

22.5 N

Explanation:

Taking towards the center to be +x, sum of forces on the child in the x direction:

∑F = ma

F = m v² / r

F = m (ωr)² / r

F = m ω² r

Plugging in values:

F = (11.5 kg) (12 rev × 2π rad/rev / 27.4 s) (0.711 m)

F = 22.5 N

muscle endurance

explanation:

i can do 50 in a row ( but i get so tired after that)

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s