a ball rolling down a hill
a skater gliding across the ice
a plane flying through the air
a car starting to move after the light changes from red to green
A team of dogs pulls a sled across the snow. The weight of the loaded sled is 2,200 N. The coefficient of friction is 0.15. How hard must the dogs pull so that their effort just equals the frictional force?
220 N
330 N
15,000 N
34 N
A force of 8,480 N is applied to a cart to decelerate it at a rate of 32.0 m/s2. What is the mass of the cart?
865 kg
377 kg
265 kg
27.0 kg
The source of the centripetal force that arises when a runner rounds a curve on a track is _____.
tension
friction
weight
gravity
An athlete prepares to throw a 2.0kilogram discus. His arm is 0.75 meters long. He spins around several times with the discus at the end of his outstretched arm so that the discus reaches a velocity of 5.0 m/s. What is the centripetal force acting on the discus?
9.4 N
14 N
27 N
66 N
Please help me, I need these answers asap! thanks.
1 Answer

you did not give any numbers to your questions. here are the answer in the same order.
1) a car starting to move after the light changes from red to green
2) pulling force of dogs fL = us N = 0.15 x2200 = 330 N
3) mass of the cart m = F / a = 8480 / 32 = 265 kg
4) the source of centripetal force for the runner is — friction
5) centripetal force on the disc fc = m v^2 / r = 2 x 5 x 5 / 0.75 = 66 N.