Mechanics | Relativity Answers

A car moving along a straight highway with speed of 126 km/h is brought to a stop within a distance of 200 m. What is the retardation of the car and how long does it take for the car to stop?

A vehicle of mass, m, kg, accelerates uniformly from rest to velocity of v, km/h, in a time of t, s, whilst ascending a gradient. The frictional resistance to motion is Fr (kN).

Compare and contrast the use of D-alembert's principle with the principle of conservation of energy when solving problems given below.

a) tractive effort between the wheels and the road surface
b) the work done in ascending the slope
c) the average power developed by the engine

A projectile is fired uphill over ground with slope at an angle α to the horizontal, Find the direction in which it should be aimed to achieve the maximum range.

A target is suspended 2m horizontally away and 0.1m above a mirror, as shown below. What is the angle of incidence of the laser if it hits the target?

A vector D = [ 30 cm , 50 degree ] and vector F = [ 45 cm , 150 degree ]
Use the graphic method to find the magnitude and direction of the sum R = D + F ?

A ball is thrown vertically upward with un initial speed of 20 m/s .Two second later a stone is thrwon vertically from the same initial height as the ball with an initial speed of 24 m/s .At what height above the release point will the ball and stone pass each other ?

Suppose you are standing on a boat in the ocean looking out at a person swimming in the water. The waves swell under your boat at a frequency of 0.80 Hz, while traveling with a wave speed of 1.5 meters per second. At any given moment, you count that there are exactly 6 complete waves between you and the swimmer. How far away is the swimmer?

Prove graphically and anatically following equations of motions;
1.) v = u+at
2.)v[sup]2[/sup] = u[sup]2[/sup]+2as
3.)s = ut+1/2at[sup]2[/sup]

A playground is on the flat roof of a city school 6.00 m above the street below . The vertical wall of the building is h = 7.00 m high , forming a 1-m high railing around the playground . A ball has fallen to the street below , and a passerby returns it by launching it at an angle of = 53.0 above the horizontal at a point d = 24.0 m from the base of the building wall . The ball takes 2.20 second to reach a point vertically above the wall .
1- Find the speed at which the ball was launched ?
2- Find the vertical distance by which the ball clears the wall ?
3- Find the horizontal distance from the wall to the point on the roof where the ball lands ?
i answer number speed = 18.1 m/s and number 2 vertical distance = 1.13 m
i need help for number 3 ?????

q1 to q3 is 20.0mm and q2 to q3 is 10.0mm on striaght line and q1 is -4.00pc q2 is -6.00pc and q3 is 1.00pc find the net electrostatic force on q2, in n due to q1 and q3