An object with a mass of 20kg changes position as a function of time according to the expression r = 4t ^ 2i + 5j, where r is expressed in meters and t in seconds. a) What is the expression of velocity as a function of time of the object? b) What is the expression of acceleration as a function of time of the object? c) What is the position, velocity and acceleration of the object at t = 3s? d) What is the force of the object and in what direction is it heading (east, north, west or south)?

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

True will be your answer dude

The disturbance in a transverse wave is perpendicular to the wave motion.unlike a transverse wave, the disturbance in a longitudinal wave is parallel to the wave motion (a), that is, back and forth.

The waves slow downn