Which of the following is a good example of a contact force? A. Earth revolving around the Sun
B. a bridge suspended by cables
C. a ball falling downward a few seconds after being thrown upward
D. electrically charged hairs on your head repelling each other and standing up

An charge with mass m and charge q is emitted from the origin, (x,y)=(0,0). a large, flat screen is located at x=l. there is a target on the screen at y position y(h), where y(h) > 0. in this problem, you will examine two different ways that the charge might hit the target. ignore gravity in this problem. 1.assume that the charge is emitted with velocity v(0) in the positive x direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive y direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l. 2.now assume that the charge is emitted with velocity v(0) in the positive y direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive x direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l.

An object with a speed of 10 m/s is moving in a direction of 30 degrees above the positive x-axis. the y-component of its velocity vector is most nearly

5volt is supplied to an electrical circuit.if the resistance of the circuit is 2.5ohms ,calculate the current flowing through the circuit.