Arunner whose mass is 54 kg accelerates from a stop to a speed of 7 m/s in 3 seconds. (a good sprinter can run 100 meters in about 10 seconds, with an average speed of 10 m/s.) (a) what is the average horizontal component of the force that the ground exerts on the runner's shoes? (b) how much work is done on the point-particle system by this force?

Acar moves at 12m/s and coasts up a hill with a uniform acceleration of -1.6m/s2. how far has it traveled after 6.0s?

Suppose that a mass of 2 kg is attached a spring whose spring constant is 50. the system is damped such that b = 12 . the mass is set in motion with an initial velocity of -8 m/s at a position 0 meters from equilibrium. set up and solve a differential equation that models this motion. write your solution in the form a cos ( ω t − α ) where α is a positive number. use your solution to fill in the information below: what is the amplitude of the motion? what is the value of ω ? what is the phase shift?

Earth's atmosphere is composed of mostly two gases. name the two gases that make up the majority of the atmosphere and use the pie chart to tell the percentages of each.