You have been called to testify as an expert witness in a trial involving a head-on collision. Car A weighs 1515 lb and was traveling eastward. Car B weighs 1125 lb and was traveling westward at 43.0 mph. The cars locked bumpers and slid eastward with their wheels locked for 18.5 ft before stopping. You have measured the coefficient of kinetic friction between the tires and the pavement to be 0.750. What speed o (in miles per hour) was car A traveling just before the collision? (This problem uses English units because they would be used in a U.S. legal proceeding.) UF mph

A block of wood that has a mass of 5 kg rests on a horizontal surface. A horizontal force of 20 N was applied to the block but the block remains at rest, solve the following: (a) the friction force between the surface and the block. (b) the normal force on the block. (c) the coefficient of static friction.

If a block of mass 889g is being pulled with a force of 2.2N parallel to a horizontal surface with a max static friction coefficient of 0.801, but the block remains at rest what is the static friction force on the block (in unit of N)?

The drag force, Fa, imposed by the surrounding air on a vehicle moving with velocity Vis given by Fa Ca ApV²/2 where Ca is a constant called the drag coefficient, A is the projected frontal area of the vehicle, and p is the air density. An automobile is moving at V = 40 miles per hour with C = 0.28, A = 24 ft², and p = 0.075 lb/ft³. Determine the force, in lbf, and the power, in hp, required to overcome aerodynamic drag.

A 8 kg block experiences a net force in the opposite direction of its velocity for 2 s. Its velocity decreases by14 m/s. What is the magnitude of the net force? Calculate answer to one decimal.

At an accident scene on a level road, investigators measure a car’s skid mark to be 112 m long.  It was a rainy day and the coefficient of friction was estimated to be 0.42.  Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes.

Many physical properties, such as force and mass, cannot be measured directly. Rather, some other physical property is measured and the desired physical property is computed from the results. For example, a bathroom scale does not actually measure mass or "weight," but rather the compression distance of a spring. The numerical values on the scale are calibrated from the compression distance using basic physics principles such as Newton's second law. Coefficients of friction cannot be measured directly. In this problem, we are going to learn how we can indirectly measure the coefficient of kinetic friction between two surfaces by directly measuring the expansion of a spring. Consider a 5.45 kg5.45 kg block that is dragged by a spring on a (relatively) frictionless horizontal surface at constant velocity. Suppose the block reaches a rough patch and the spring stretches by 5.25 cm5.25 cm. Compute the coefficient of kinetic friction ?μ between the block and the rough patch if the spring…

(a) A 900 kg van is traveling at a constant speed of 1.38 m/s due north. What is the total force (in N) on the vehicle? (Assume north is the positive direction. Indicate the direction with the sign of your answer.) (b) What is the total force on the van (in N) if it is moving due south? (Assume north is the positive direction. Indicate the direction with the sign of your answer.)

A car of mass 6000 kg moving at 40 m/s is suddenly brought to a stop when a deer crosses the road. If a braking force of 600,000 N/m is needed to bring the car to a stop, what was the duration of the force?

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