Master the Art of Physics: Comprehensive Examples and Expert Advice

In an inkjet printer, letters are built up by squirting drops of ink horizontally at a sheet of paper from a rapidly moving nozzle. The Pattern on the paper is controlled by an electrostatic valve that determines at each nozzle position whether ink is squirted onto thepaper or not. The ink drops have a radius 15.0${\displaystyle \mu m}$ and leave the nozzle and travel horizontally toward the paper at speed v=18.0 m/s . The drops pass through a charging unit that gives each drop a positive charge by causing it to lose some electrons. The drops then pass between parallel deflecting plates of length ${\displaystyle D_0=2.45}$ cm , where there is a uniform vertical electric field with magnitude ${\displaystyle E=8.40\times {10}^4}$ N/C
If a drop is to be deflected a distance d= 0.270 mm by the time it reaches the end of the deflection plate,what magnitude of charge q must be given to the drop? (Assume that the density of the ink drops 1000 ${\displaystyle k\frac{g}{m^3}}$, and ignore the effects of gravity.)

A 0.50 kg ball that is tied to the end of a 1.1 m light cord is revolved in a horizontal planewith the cord making a ${\displaystyle {30}^{\circ }}$ angle, with the vertical.

a) Determine the ball speed.
b) If, instead, the ball is revolved so that its speed is 4.0 m/s,what angle does the cord make with the vertical?
c) If the cord can withstand a maximum tension of 9.1 N, what is the highest speed at which the ballcan move?

A 292 kg motorcycle is accelerating up along a ramp that is inclined 30.0° above the horizontal. The propulsion force pushing the motorcycle up the rampis 3020 N, and air resistance produces a force of 250 N that opposes the motion. Find the magnitude of the motorcycles

An extreme skier, starting from rest, coasts down a mountainthat makes an angle ${\displaystyle {25.0}^{\circ }}$ with the horizontal. The coefficient of kinetic friction between her skis and the snow is 0.200. She coasts for a distance of 11.9 m before coming to the edge of a cliff. Without slowing down, she skis offthe cliff and lands down hill at a point whose vertical distance is 4.20 m below the edge. How fast is she going just before she lands?

A rifle with a weight of 30 N fires a 5.0 g bullet with a speed of 300m/s. (a) Find the recoil speed of the rifle. (b) If a700 N man holds the rilfe firmly against his shoulder, find there coil speed of the man and his rifle.

Ropes 3m and 5m in length are fastened to a holiday decoration that is suspended over a town square. The declaration has a mass of 5kg. The ropes, fastened at different heights, make angles of 52 degrees and 40 degrees with the horizontal. Find the tension in each wire and the magnitude of each tension.

If a negative charge is initially at rest in an electric field, will it move toward a region of higher potential or lower potential? What about a positive charge? How does the potential energy of the charge change in each instance?

Problem: A 0.500kg block attached to a spring with the length 0.60m and force constant k=40.0 N/m is at rest with the back of the block at point A on a frictionless, horizontal airtable. The mass of the spring is negligible. You pull the block tothe right along the surface with a constant horizontal forceF=20.0-6N. 
Questions: 
A.) What is the blocks

A rocket is fired in deep space, where gravity is negligible. In the first second it ejects of ${\displaystyle \frac{1}{160}}$ its mass as exhaust gas and has an acceleration of ${\displaystyle 16.0\frac{m}{s^2}}$. 
What is the speed of the exhaust gas relative to the rocket?

A 1.0 kg ball and a 2.0 kg ball are connected by a 1.0-m-long rigid, massless rod. The rod is rotating cw about its center of mass at 20 rpm. What torque will bring the balls to a halt in 5.0 s? Answer in Nm.

A lunch tray is being held in one hand, as the drawing illustrates. The mass of the tray itself is 0.200 kg, and its center of gravity is located tits geometrical center. On the tray is a 1.00 kg plate of food and a 0.190 kg cup of coffee. Obtain the force T exerted by the thumb and the force F exerted by the four fingers. Both forces act perpendicular to the tray, which is being held parallel to the ground.

An 80.0-kg skydiver jumps out of a balloon at an altitude of1000 m and opens the parachute at an altitude of 200 m. (a) Assuming that the total retarding force on the diver is constant at 50.0 N with the parachute closed and constant at 3600 N with the parachute open, what is the speed of the diver whenhe lands on the ground? (b) Do you think the skydiver will be injured? Explain. (c) At what height should the parachute be opened so that the final speed of the skydiver when he hits the ground is 5.00m/s? (d) How realistic is the assumption that the total retarding force is constant? Explain.

A conducting sphere of radius 0.01m has a charge of ${\displaystyle 1.0\times {10}^{-9}C}$ deposited on it. The magnitude of the electric field in N/C justoutside the surface of the sphere is: 
a. 0 
b. 450 
c. 900 
d. 4500 
e. 90000

A coin with a diameter of 2.40cm is dropped on edge on to a horizontal surface. The coin starts out with an initial angular speed of 18.0 rad/s and rolls in a straight line without slipping. If the rotation slows with an angular acceleration of magnitude 1.90 rad/s, how far does the coin roll before coming to rest?

A weatherman carried an aneroid barometer from the groundfloor to his office atop a tower. On the ground level, the barometer read 30.150 in Hg absolute; topside it read 28.607 in hg absolute. Assume that the average atmospheric air density was 0.075lb/ft3, estimate the height of the building.

A clay vase on a potter's wheel experiences an angular acceleration of ${\displaystyle 8.00\frac{rad}{{\sec }^2}}$ due to the application of 10.0Nm net torque. Find the total moment of inertia of the vase and the potter's wheel.

The eye of a hurricane passes over Grand Bahama Island. It is moving in a dirction 60.0 degrees north of west with a speed of 41.0 km/h. Three hours later, the course of the hurricane suddenly shifts due north, and its speed slows to 25.0 km/h. How far from Grand Bahama is the hurricane 4.50 h after it passesover the island?