The drawing shows a version of the loop-the-loop trick for a small car. If the car is given an initial speed of 4 m/s, what is the largest value that the radius r can have if the car is to remain in contact with the circular track at all times?
A block is on a frictionless table, on earth. The block accelerates at when a 10 N horizontal force is applied to it. The block and table are set up on the moon. The acceleration due to gravity at the surface of the moon is . A horizontal force of 5N is applied to the block when it is on the moon. The acceleration imparted to the block is closest to:
An exceptional standing jump would raise a person 0.80 m off the ground. To do this, what force must a 66-kg person exert against the ground? Assume the person crouches a distance of 0.20 m prior to jumping, and thus the upward force has this distance to act over before he leaves the ground.
Four very long, current-carrying wires in the same plane intersect to form a square with side lengths of 45.0 cm, as shown in the figure blelow. The currents running through the wires are 8.0 A, 20.0 A, 10.0 A, and I.
Find the magnitude of the current I that will make the magnetic field at the center of the square equal to zero.
What is the direction of the current I (up or down)?