Mechanics | Relativity Answers

A steel plate measures 500mm×200mm×10mm. If the relative density of the steel is 7.8 ,calculate the mass of the plate

A crate of mass 10.0 kg is pulled up a rough incline with an initial speed of 1.50 m/s. The

pulling force is 100 N parallel to the incline, which makes an angle of 20.0° with the

horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.00 m.

(a) How much work is done by the gravitational force on the crate? (b) Determine the

increase in internal energy of the crate – incline system due to friction. (c) How much work is

done by the 100-N force on the crate?(d) What is the change in kinetic energy of the crate?

(e) What is the speed of the crate after being pulled 5.00 m?

A car reaches a velocity of 20m/s with an acceleration of 2m/s

2

. How far will it travel while it is 

accelerating if it (a) Initially at rest? (b). initially moving at 10m/s

A biophysicist seeks to separate subcellular particles with an analytic ultracentrifuge. The biophysicist must determine the magnitude of centripetal acceleration provided by the centrifuge of various speeds and radii.

Calculate the magnitude of centripetal acceleration at 8.4 cm from the centre of the centrifuge when it is spinning at 6.0 x 10^4 RPM. Find the answer in terms of g.

^{Patrons on an amusement park ride called the Rotor stand with their backs against the wall of a rotating cylinder while the floor drops away beneath them. To keep from sliding downward, they require a centripetal acceleration in excess of about 25 ms^-2. The rotor has a diameter of 5.0 m. What is the minimum frequency for its rotation?}

a. What is the magnitude of centripetal acceleration due to the daily rotation of an object at earth's equator. The equatorial radius is 6.38x10^6 m.

b. How does this acceleration affect a person's weight at the equator?