Mechanics | Relativity Answers

When a mass of 40 g is attached to a vertically hanging spring it extends by 0.4 cm. Find :
(i) Force constant of the spring.
(ii) The extension when 100 g weight is attached to it.
(iii) The time period of oscillation of 100 g weight on it.
(iv) The time period and force constant if the spring is cut in three equal parts and 100 g weight is made to oscillate on one part.

Explain what happens when a body is raised to a height from the surface of earth and then given a horizontal velocity v such that:
i) 0 < v < 8.0 km/s
ii) v = 8.0 km/s
iii) 8.0 < v < 11.2 km/s
iv) v = 11.2 km/s

boat 'a' is moving with speed of 10 km/h in west direction. in 100 km south of a is boat 'b' moving towards north (speed of boat 'b' is also 10 km/h). in what time will the two boats be at the shortest distance from each other

A square lamina has a side of length l. If an isosceles triangle is removed such that its base lies on one side of the square and its height is h. If the remaining portion is suspended from its apex p of the cut will remain in equilibrium in any position. Find the value of h

A ball is thrown horizontally at a speed of 20 m/s from the top of a 30 m cliff. After 1 second, what is the horizontally speed of the ball

There is an unknown container on a horizontal surface that you need to

move. The coefficient of friction for the floor is 0.54 and the box

weighs 250kg. If you apply a force of 350N at an angle of 50 degrees

the box will accelerate at a rate what rate?

Astrology, that unlikely and vague psuedoscience, makes much of the position of the planets at the moment of birth. The only known force a planet exerts on earth is gravitational.
a) Calculate the gravitational force exerted on a 3.00 kg baby by a 90 kg father 0.150 away at birth (assisting so he is close).
b)Calculate the force on the baby due to Jupiter if it is at its closest to earth, some 6.29xe11 m away, showing it to be comparible to that of the father. The mass of Jupiter is about 1.90x e27 kg. Other objects in the room and the hospital building also exert similar gravitational forces. (of course, there could be unknown force acting, but scientist first need to be convinced that there is even an effect, much less that an unknown force causes it.)

a very light ideal spring having a spring constant of 8.2 N/cm is used to lift a 2.2 kg tool with an upward acceleration of 3.25 m/s^2. if the spring has negligible length when it is not stretched, how long is it while it is pulling the tool upward?

a weightless rod is acted upon by parallel force of 4 N and 2 N at the ends .length of rod is 3 m . to keep rod in equilibrium 6 N should be applied where

A circular disk of mass 0.3 kg and radius 31 cm, initially not rotating, slips down a thin spindle onto a turntable (disk) of mass 1.9 kg and the same radius, rotating freely at 4.5 rad/s.

a) Find the new angular velocity of the combination;
b) The change in the kinetic energy?
c) If the motor is switched on after the disk has landed, what is the constant torque needed to regain the original speed in 3.3 s?