Mechanics | Relativity Answers

Launched from the ground, a rocket accelerates vertically upward at 4.6 m/s2. It passes through a band of clouds 5.3 km thick, extending upward from an altitude of 1.9 km. How long is it in the clouds?

The position of an object as a function of time is given by , where b is a constant. Find an expression for the instantaneous velocity as a function of time, and show that the average velocity over the interval from to any time t is one-fourth of the instantaneous velocity at t.

The greatest height reported for a jump into an airbag is 99.4 m by stuntman Dan Koto. In 1948 he jumped from rest from the top of the Vegas World Hotel and Casino. He struck the airbag at a speed of 39 m/s (88 mi/h). To assess the effects of air resistance, determine how fast he would have been traveling on impact had air resistance been absent.

Two tuning forks are sounded at the same time.
Which tuning forks will give a beat frequency of 20 Hz when sounded with a 240 Hz tuning fork?
12 Hz
260 Hz
4800 Hz
220 Hz

What is the beat frequency heard for each pair of tuning forks below?
300 Hz and 325 Hz 360 Hz and 380 Hz 480 Hz and 510 Hz

Place the following under the proper column above:
625 Hz
740 Hz
990 Hz
20 Hz
30 Hz
25 Hz

A block of mass 6.00kg initially at rest is pulled to the right by a constant
horizontal force with magnitude 12.0N. The coefficient of kinetic friction
between the block and the surface is 0.150.
(a) Find the speed of the block after it has moved 3.0m
(b) Suppose the force F is applied at an angle φ. At what angle should the force
applied to achieve the largest possible speed after the block has moved 3.0m
to the right?

Two identical guitar strings are prepared such that they have the same length (1.91 m) and are under the same amount of tension. The first string is plucked at one location, primarily exciting the 3rd harmonic. The other string is plucked in a different location, primarily exciting the 5th harmonic. The resulting sounds give rise to a beat frequency of 333 Hz. What is the wave propagation speed on the guitar strings? Please answer in m/s.

A spring oscillator is designed with a mass of 0.110 kg. It operates while immersed in a damping fluid, selected so that the oscillation amplitude will decrease to 1.00% of its initial value in 9.12 s. Find the required damping constant for the system. Please Answer in kg/s

The planet Jupiter has an elliptical orbit with e = 0.05 and a semi-major axis of
8.7 10 m.
11 × Calculate the energy of the planet, perihelion and aphelion distances and the
speed of the planet at these points.

Three point masses of 3 kg each have the following position vectors:
r i k r j k r i j mˆ 3 mˆ
; ( ) 3( )1 m ˆ 3 mˆ
( ) 4 mˆ m ˆ
( ) 2( 3 )
2 2 2
1 2 3
t = t + t + t ; t = t + t = t − + t
r r r
Determine the velocity and acceleration of the centre of mass of the system.

The potential energy (in J) of a system in one dimension is given by:

2 3 U (x) = 5 − x + 3x − 2x
What is the work done in moving a particle in this potential from x = 1 m to x = 2 m? What
is the force on a particle in this potential at x = 1 m and x = 2 m? Locate the points of stable
and unstable equilibrium for this system.