Mechanics | Relativity Answers

A truck gradually starts off from rest with a uniform acceleration of 2 m/s2 . It reaches a velocity of 16 m/s. Using the equation v2 = u2 + 2as, calculate the distance it travels while it is accelerating.

A car accelerates from 20 m/s to 30 m/s in 10 s. (a) Calculate the car’s acceleration using v = u + at. (b) Draw a velocity–time graph to show the car’s motion. Find the distance it travels by calculating the area under the graph. (c) Check your answer by using the equation s = ut + ½at2 

Chris jumps off a bridge with a bungee cord (a heavy stretchable cord) tied around his ankle, (Figure 1). He falls for 15 m

m before the bungee cord begins to stretch. Chris's mass is 80.0 kg

kg and the cord stop his fall (momentarily) after he has fallen a distance of 59.0 N/m

N/m m from the bridge.

Calculate Chris's gravitational potential energy when the cord just begins to stretch (position b), relative to: the bridge (position a)., the stopping point (position c).

A stone is projected from the ground level with an initial speed 𝑣0 directed 350 above the horizontal. Five seconds later, it lands on a cliff 8 m high.

a) What is the magnitude of the initial velocity of the stone?

b) What is the horizontal and vertical component of its velocity and velocity magnitude just before the stone hits the cliff?

c) How far from the release point horizontally does the stone hit the cliff?

A particle follows a spiral orbit given by r = c (theta)² under an unknown force law. Prove that such an orbit is possible in a central field. Also find the force law?

What is the density of a cylindrical bar of radius 5.4 mm and length 10.8 cm that has a mass of 68 g? (in kg m⁻³ to 2.s.f)

Note:

The volume  of a cylinder is given by  where  is the radius of the cylinder and  is the length.

The density  is calculated using  where  is the mass of the object and  is the volume.

A person throws a baseball with a horizontal component of velocity of 25 m/s. After 2 seconds, the ball is 40 m. above the release point. Calculate the horizontal distance it has traveled by this time, it’s initial vertical component of velocity, and it’s initial angle of projection. Also, is the ball on the way up or the way down at this moment in time?

A light source emits light of wavelength 125 nm while at rest. When the source is moving, the Doppler shifted wavelength of the emitted light is 375 nm. Is the source of light approaching us or receding from us? Also calculate its speed.

Find the greatest angle through which a nonrelativistic alpha partiClec can be deflected by striking a stationary proton.[14°]

An object is to be dropped from an aeroplane so as to hit a target on the ground. If the aeroplane is travelling horizontally at 80m/s at a height of 2000m, calculate the position of the aeroplane when the object is released. And the time for the object to hit target from the target from the instant of release.