Exam 5: Further Applications of Newtons Laws

A boy on board a cruise ship drops a 30.0 gm marble into the ocean. If the resistive force proportionality constant is 0.500 kg/s, what is the terminal speed of the marble in m/s?

The Hills Motorway in Sydney has a number of lanes for traffic. For traffic going in one direction, the radius for the inside of the curve is half the radius for the outside. One car, car A, travels on the inside while another car of equal mass, car B, travels at equal speed on the outside of the curve. Which statement about resultant forces on the cars is correct?

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air:

A car enters a level, unbanked semicircular hairpin turn of 100 m radius at a speed of 28 m/s. The coefficient of friction between the tyres and the road is $\mu$ = 0.800. If the car maintains a constant speed of 28 m/s, it will:

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 500 m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

An extremely drunk physics student, while on holiday in the Snowy Mountains, decides to snowboard down a hill on a bathroom scale (don't ask us why …). The student has a mass of 60 kg, the bathroom scale has a mass of 3 kg and the icy hill a slope of 20°. Assume there is no frictional force between the bottom of the scale and the hill. The static friction force the scale exerts on the person is:

Frank says that if you release the string when swinging a ball in a horizontal circle, the ball flies out in the radial direction defined by the string at the instant you release the ball. John says that it flies out along a tangent line perpendicular to the string, and that it then drops straight down to the ground. Which one, if either, is correct?

Two blocks are accelerated across a horizontal frictionless surface as shown. Frictional forces keep the two blocks from sliding relative to each other, and the two move with the same acceleration. If F = 1.2 N and M = 1.0 kg, what is the horizontal component (frictional force) of the force of the large block on the small block?

The coefficient of kinetic friction between the surface and the larger block is 0.25, and the coefficient of kinetic friction between the surface and the smaller block is 0.40. If F = 22 N and M = 1.0 kg in the figure, what is the magnitude of the acceleration of either block?

A rock attached to a string swings in a vertical circle. Which free body diagram could correctly describe the force(s) on the rock when it is at the highest point?

An aircraft pilot experiences weightlessness as she passes over the top of a loop-the-loop manoeuvre. If her speed is 200 m/s at the time, find the radius of the loop.

A 0.30-kg mass attached to the end of a string swings in a vertical circle (R = 1.6 m), as shown. At an instant when $\theta$ = 50 $\degree$ , the tension in the string is 8.0 N. What is the magnitude of the resultant force on the mass at this instant?

Two small cylindrical plastic containers with flat bottoms are placed on a turntable that has a smooth flat surface. Canister A is empty; canister B contains lead shot. Each canister is the same distance r from the centre. The coefficient of static friction between the canisters and the turntable is $\mu$ s. When the speed of the turntable is gradually increased,

The frictional force of the floor on a large suitcase is least when the suitcase is:

A wasp circles around a beer can at constant speed once per second in a path with a 12-cm diameter. We can conclude that the wasp's wings must push on the air with force components that are:

An airplane moves 140 m/s as it travels around a vertical circular loop which has a 1.0-km radius. What is the magnitude of the resultant force on the 70-kg pilot of this plane at the bottom of this loop?

A space station in the form of a large wheel, 120 m in diameter, rotates to provide an 'artificial gravity' of 3.00 m/s2 for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.

The equation below is the solution to a problem. $\frac{(2.00 \mathrm{~kg})\left(8.00 \frac{\mathrm{~m}}{\mathrm{~s}}\right)^{2}}{5.00 \mathrm{~m}}=6.00 \mathrm{~N}-(2.00 \mathrm{~kg})\left(9.80 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}\right)\left(\cos 180^{\circ}\right)$ .The best physical representation of this equation is:

The following equation was obtained by solving a physics problem: $\frac{\left(16.0 \frac{\mathrm{~m}}{\mathrm{~s}}\right)^{2}}{(75.0 \mathrm{~m})\left(9.80 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}\right)}=\tan 19.2^{\circ}$ The best physical representation of the situation is:

The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction $\mu$ k is least when the force is applied at an angle $\theta$ such that: