A four-person bobsled (total mass =630 kg) comes down a straightaway at the start of a bobsled run.The straightaway is 80.0 m long and is inclined at a constant angle of 10.2 with the horizontal. Assume that the combined effects of friction and air drag produce on the bobsled a constant force of 62.0 N that acts parallel to the incline and up the incline. Answer the following questions to three significant digits. (a) If the speed of the bobsled at the start of the run is 6.20 m/s, how long does the bobsled take to come down the straightaway? (b) Suppose the crew is able to reduce the effects of friction and air drag to 42.0 N. For the same initial velocity, how long does the bobsled now take to come down the straightaway?

A car (m = 1790 kg) is parked on a road that rises 17° above the horizontal. What are the magnitudes of (a) the normal force and (b) the static frictional force that the ground exerts on the tires?

In the figure, a block of mass m = 3.71 kg is pulled along a horizontal frictionless floor by a cord that exerts a force of magnitude F = 12.7 N at an angle 0 = 26.0°. (a) What is the magnitude of the block's acceleration? (b) The force magnitude F is slowly increased. What is its value just before the block is lifted (completely) off the floor? (c) What is the magnitude of the block's acceleration just before it is lifted (completely) off the floor? (a) Number i Units (b) Number i Units (c) Number i Units > >

A car (m = 1600 kg) is parked on a road that rises 12° above the horizontal. What are the magnitudes of (a) the normal force and (b)the static frictional force that the ground exerts on the tires?

The box below has been given an initial velocity of 2.60 m/s directed up the ramp. The angle the incline makes with the horizontal is 34.0°. The coefficient of static friction between the box and the ramp is 0.430 while the coefficient of kinetic friction between the box and the ramp is 0.280. Use g = 9.80 m/s2. (a) Calculate the magnitude of the box's acceleration while it is sliding up the ramp. m/s2 (b) How far (measured parallel to the incline) does the box travel before coming instantaneously to rest? m (c) After the box comes instantaneously to rest on the ramp, it then either starts sliding down, or remains at rest. Either enter 0, if you determine that the box remains at rest, or calculate the magnitude of the box's acceleration while it is sliding back down the ramp. m/s2

In the figure, a block of mass m = 5.44 kg is pulled along a horizontal frictionless floor by a cord that exerts a force of magnitude F = 10.6 N at an angle 0 = 24.0°. (a) What is the magnitude of the block's acceleration? (b) The force magnitude F is slowly increased. What is its value just before the block is lifted (completely) off the floor? (c) What is the magnitude of the block's acceleration just before it is lifted (completely) off the floor? (a) Number Units (b) Number Units (c) Number Units

A block of mass 11 kg lies on a horizontal plane. A force F that is inclined 42.3° with the horizontal is applied to the block (pulled the block) causing it to move 15 meters in 5 seconds. If the coefficient of friction between the block and the horizontal surface is 0.3, find the magnitude (N) of the force F. Round off only on the final answer expressed in 3 decimal places.

A student of mass 61.4 kg, starting at rest, slides down a slide 22.2 m long, tilted at an angle of 28.1° with respect to the horizontal. If the coefficient of kinetic friction between the student and the slide is 0.118, find the force of kinetic friction, the acceleration, and the speed she is traveling when she reaches the bottom of the slide. (Enter the magnitudes.) HINT (a) the force of kinetic friction (in N) N (b) the acceleration (in m/s) m/s? (c) the speed she is traveling (in m/s) m/s Need Help? Read It Watch

A sphere of mass 4.7 × 10-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 26° with the vertical. Find (a) the magnitude of that push and (b) the tension in the cord.

You must push a crate across a floor to a docking bay. The crate weighs 183 N. The coefficient of static friction between crate and floor is 0.500, and the coefficient of kinetic friction is 0.300. Your force on the crate is directed horizontally. (a) What magnitude of your push puts the crate on the verge of sliding? (b) With what magnitude must you then push to keep the crate moving at a constant velocity? (c) If, instead, you then push with the same magnitude as the answer to (a), what is the magnitude of the crate's acceleration? (a) Number i (b) Number (c) Number i Units Units Units