Mechanics | Relativity Answers

In a women's 100-m race, accelerating uniformly, Laura takes 1.82 s and Healan 3.07 s to attain their maximum speeds, which they each maintain for the rest of the race. They cross the finish line simultaneously, both setting a world record of 10.4 s.

A projectile of mass 50kg is shot vertically upwards with an initial velocity of 100m/s. After 5s, it explodes into two fragments, one of which having mass 20kg travels vertically up with a velocity of 150m/s. What is the velocity of the other particile at that instant? Calculate the sum of momenta of the fragments 4s after explosion and show that it is equal to the momentum of the projectile at that instant if there were no explosion. (take g=9.8m/s2)

Suppose a spring-mass system has 18Nm 1 −
k = and m = 0.71kg. The system is
oscillating with an amplitude of 54 mm. (i) Determine the angular frequency of
oscillation. (ii) Obtain an expression for the velocity v of the block as a function of
displacement, x and calculate v at x = 34 mm. (iii) Obtain an expression for the mass’s
distance | x | from the equilibrium position as a function of the velocity v and calculate | x |
when v = 0.18 ms−1. (iv) Calculate the energy of the spring-mass system.

two identical balls traveling parallel to the x-axis have speed of 30cm/s and are oppositely directed.they collide perfectly elastically. after the collision, one ball is moving at an angle of 30 degrees above the x-axis.find its speed and the velocity of the other balls.

how two farces are added up if they are not concurrent but in same direction ?

A projectile is fired from the top of a cliff of height h above the ocean below. The projectile is fired at an angle θ above the horizontal and with an initial speed vi.
(a) Find a symbolic expression in terms of the variables vi, g, and θ for the time at which the projectile reaches its maximum height.
(b) Using the result of part (a), find an expression for the maximum height hmax above the ocean attained by the projectile in terms of h, vi, g, and θ

A ski jumper launches from a ski jump that is oriented parallel to a hill. The jump has a vertical drop of 50 m and the coefficient of friction \mu between the skier and the jump is 0.05. The launch point is 5 m above the hill and there is a small lip at the bottom of the jump so that the skier launches horizontally. How long in seconds is the skier in flight?

the 30kg boy stands on a horizontal plank 1m from one end and 2m from the other. the plank is uniform and has a mass of 10kg. calculate the force

A 1.70 m wide, 1.40 m high, 1300 kg car hits a very slick patch of ice while going 20.0 m/s. Air resistance is not negligible. How long will it take until the car's speed drops to 16 m/s?

a sheet of aluminum of thickness 20 mm is cut with vertical machine that have blade of length 10 cm and width 0.2 cm while cutting the blades each exert a force of 30 N on the sheet . the length of each blade that makes contact with the sheet is approximately 0.5 mm calculate the shear stress on the sheet???