Mechanics | Relativity Answers

If a cessna 172 requires 15 seconds to reach its life off speed of 145 km/hr what is its average acceleration?

. Mary and Sally are in a foot race (Fig. 2). When Mary is 22 m from the finish line, she has a speed of 4.0 m/s and is 5.0 m behind Sally, who has a speed of 5.0 m/s. Sally thinks she has an easy win and so, during the remaining portion of the race, decelerates at a constant rate of 0.4 m/s2 to the finish line. What constant acceleration does Mary now need during the remaining portion of the race, if she wishes to cross the finish line sideby-side with Sally?

2. N’dea, an ACCESS student, has a mass of 87.5 kg. Her new bicycle has a mass of 14.6 kg. N’dea is pedaling so that a net (unbalanced) force of 7.87 N accelerates her and her bicycle. What is the value of the acceleration
?

A block being pulled to the right by a 10N force acting 30° above the horizontal undergoes uniform motion on a level surface . The coefficient of sliding friction between the block and the surface is 0.4 what is the acceleration of the block

An insect of mass 20 g crawls from the centre to the outside edge of a rotating disc of
mass 200g and radius 20 cm. The disk was initially rotating at 22.0 rads−1
. What will be
its final angular velocity? What is the change in the kinetic energy of the system?

A car increases its speed from 60km/hr to 65km/hr while a bicycle goes from rest to 3 m/s, which undergoes greater acceleration after both travels in 10 seconds?

A pendulum bob of mass 50 g is suspended on a string from the ceiling of an elevator which is moving downwards with an acceleration 1.5 ms-2. Draw the free body diagram using the non-inertial frame of reference and determine the tension in the string. (Take g = 10 ms-2)

A solid cylinder of mass 3.0 kg and radius 1.0 m is rotating about its axis with a speed of 40 rad s-1. Calculate the torque which must be applied to bring it to rest in 10s. What would be the power required?

An automobile travelling at 80 km hr-1 has tyres of radius 80 cm. On applying brakes, the car is brought to a stop in 30 complete turns of the tyres. What is the magnitude of the angular acceleration of the wheels? How far does the car move while the brakes are applied?

A simple harmonic motion is represented by
x(t)=cos omega t
Obtain expressions for velocity and acceleration of the oscillator. Also, plot the time variation of displacement, velocity and acceleration of the oscillator.