1) a force acts at an angle of 28.0 degrees above the horizontal on a sled and moves it 98.0m across a horizontal surface. If the work done by this force on the sled is 2.80 x 10^8 J, what is the magnitude of the force? 2) a mass of 45.0kg is travelling at 7.59m/s. If the kinetic energy of the mass is increased by 4.5 x 10^3 J, what is its final speed? 3) what is the outer radius of a car tire that has a tangential speed of 36.0 m/s and period of rotation of 5.60 x 10^-2 s? 4) an elevator and its passengers have a total mass of 1.75 x 10^3 kg. When the elevator starts up, the motor exerts force of 1.85 x 10^4 N[up] on the elevator over a displacement of 1.44 m [up]. What is the change in kinetic energy of the elevator? 5) the moon ariel orbits uranus with an average radius of 1.91 x 10^8 m once every 2.18 x 10^5 s. If the uranus' moon tatiana orbits with a radius of 4.36 x 10^8 m, what would you expect its period to be? 6) a 4.50 kg mass is shown at rest against a spring which has an elastic constant of 7.60 x 10^3 N/m. At that instant, the soring is compressed a distance (x) of 12.0cm from its rest position and is 0.350 m above the base of the frictionless inclined plane. When the mass is released, the spring accelerates it uo the olane. What will be the soeed of the mass when it reached a height if 1.20m above the base of the plane? 7) a 3.60 kg block slides down an inclined plane. When the block is 3.50 m above the ground, it has a soeed of 1.80 m/s. When it reached a height of 1.25 m above the ground, it has a soeed of 4.20m/s. What is the change in mechanical energy of the block