Exam 6: Applications of Newtons Laws

A 1000-kg car is moving at 30 m/s around a horizontal unbanked curve whose diameter is 0.20 km.What is the magnitude of the friction force required to keep the car from sliding?

A highway curve of radius 80 m is banked at 45°.Suppose that an ice storm hits,and the curve is effectively frictionless.What is the speed with which to take the curve without tending to slide either up or down the surface of the road?

A car goes around a circular curve on a horizontal road at constant speed.What is the direction of the friction force on the car due to the road?

A 250-kg motorcycle goes around an unbanked turn of radius 13.7 m at a steady 96.5 km/h.What is the magnitude of the net force on the motorcycle?

A 40-kg box is being pushed along a horizontal smooth surface.The pushing force is 15 N directed at an angle of 15° below the horizontal.What is the magnitude of the acceleration of the crate?

A car moving at a steady 10 m/s on a level highway encounters a depression that has a circular cross-section with a radius of 30 m.The car maintains its speed as it drives through the depression.What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the bottom of the depression?

A particularly scary roller coaster contains a loop-the-loop in which the car and rider are completely upside down.If the radius of the loop is With what minimum speed must the car traverse the loop so that the rider does not fall out while upside down at the top? Assume the rider is not strapped to the car.

You are driving at On a freeway curve of radius What is the magnitude of your acceleration?

A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a rope that goes over an ideal pulley.If the masses are gently released from rest,how long does it take for the 3.0-kg mass to rise by 1.0 m?

Two blocks,A and B,are being pulled to the right along a horizontal surface by a horizontal 100-N pull,as shown in the figure.Both of them are moving together at a constant velocity of 2.0 m/s to the right,and both weigh the same. Which of the figures below shows a correct free-body diagram of the horizontal forces acting on the upper block,A?

What is the proper banking angle for an Olympic bobsled to negotiate a 100-m radius turn at 35 m/s without skidding?

A 6.00-kg ornament is held at rest by two light wires that form 30° angles with the vertical,as shown in the figure.An external force of magnitude F acts vertically downward on the ornament.The tension exerted by each of the two wires is denoted by T.A free-body diagram,showing the four forces that act on the box,is shown in the figure.If the magnitude of force F is 410 N,what is the magnitude of the tension T?

Two cars go around a banked curve at the proper speed for the banking angle.One car has tires with excellent traction,while the other car has bald slippery tires.Which of these cars is more likely to slide on the pavement as it goes around the curve?

A future use of space stations may be to provide hospitals for severely burned persons.It is very painful for a badly burned person on Earth to lie in bed.In a space station,the effect of gravity can be reduced or even eliminated.How long should each rotation take for a doughnut-shaped hospital of 200-m radius so that persons on the outer perimeter would experience 1/10 the normal gravity of Earth?

A 20-g bead is attached to a light 120 cm-long string as shown in the figure.If the angle α is measured to be 18°,what is the speed of the mass?

A load is being lifted vertically upwards by means of two cables attached to it.The first cable exerts a force of 600 N at an angle of 35.0° to the left of the vertical.The second cable exerts a force of 1300 N.At what angle to the right of the vertical is the second cable pulling?

A 200-g hockey puck is launched at an initial speed of 16 m/s up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µ_s = 0.40 and µ_k = 0.30,respectively.What vertical height does the puck reach above its starting point?

If a satellite moves with constant speed in a perfectly circular orbit around the earth,what is the direction of the acceleration of the satellite?

A 3.0-kg and a 5.0-kg box rest side-by-side on a perfectly smooth,level floor.A horizontal force of 32 N is applied to the 3.0-kg box pushing it against the 5.0-kg box,and,as a result,both boxes slide along the floor.How hard do the two boxes push against each other?

Jason takes off across level water on his jet-powered skis.The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible).The skis produce a forward thrust of 200 N and have a coefficient of kinetic friction with water of 0.10.Unfortunately,the skis run out of fuel after only 90 s.What is Jason's top speed?