Mechanics | Relativity Answers

Why the mass is negative? Can you explain? Thank you in advance.

A jet flies 700km due north, then 300km west, after which it moves 400km due north and 800km east before it arrived at its destination and landed

(a) using vector notation, draw this movement.

(b) find the resultant displacement of the jet.

Given that the sound intensity 4.0 m from the sound source is 5.0 x 10−6w𝑚−2.

What is the intensity at 2.0 m?

Astronauts on the first trip to Mars take along a pendulum that

has a period on earth of 1.50 s. The period on Mars turns out to be

2.45 s. What is the free-fall acceleration on Mars?

(a) Find the value of the moment of inertia of the sphere about its axis of rotation.

(b) What is the magnitude of angular velocity of the sphere when it touches the

inclined plane?

(c) How far along the second inclined plane (45º) on the right will the center of the

sphere travel before it comes to a stop?

Is the equation v = v0 + ax dimensionally correct?

secutive standing waves occur at frequencies 280 Hz and 315 Hz on a taut

g fixed at both ends. Determine the frequency of the 4th harmonic.

A pinball machine launch ramp consisting of a spring and a 30∘ ramp of length 𝐿 as shown in Fig. 1.

(a) (3 marks) If the spring is compressed a distance 𝑥 from its equilibrium position and is then released at 𝑡 = 0, the pinball (a sphere of mass 𝑚 and radius 𝑟) reaches the top of the ramp at 𝑡 = 𝑇. Derive the expression for the spring constant 𝑘 in terms of 𝑚, 𝑔, 𝑥, and 𝐿. [Assume that the friction is sufficient, and the ball begins rolling without slipping immediately after launch.]

(b) (2 marks) What is the potential energy of the ball when it is at the midpoint of the ramp?

(c) (3 marks) Derive the expression of the speed of the ball immediately after being launched in terms of 𝑔 and 𝐿

A car acceleration of 1m/s². What is the change in its velocity after every 3 seconds?

particle at rest decays into two particles of rest mass mo and 2mo, lighter particle moves with a speed of 0.8c, find the speed of other particle in lab frame and hence find the rest mass of the original particle