Aremote-controlled car is moving in a vacant parking lot. the velocity of the car as a function of time is given by v =[5.00m/s−(0.0180m/s^3)t^2]i^ + [2.00m/s+(0.550m/s^2)t]j^. a) what is the magnitude of the velocity of the car at t = 7.93 s ? b) what is the direction (in degrees counterclockwise from +x-axis) of the velocity of the car at t = 7.93 s ? c) what is the magnitude of the acceleration of the car at t = 7.93 s ? d) what is the direction (in degrees counterclockwise from +x-axis) of the acceleration of the car at t = 7.93 s ?

Ahorizontal wire is tied to supports at each end and vibrates in its second-overtone standing wave. the tension in the wire is 5.00 n, and the node-to-node distance in the standing wave is 6.28 cm. (a) what is the length of the wire? (b) a point at an anti- node of the standing wave on the wire travels from its maximum upward displacement to its maximum downward displacement in 8.40 ms. what is the wire's mass?

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.