Mechanics | Relativity Answers

A gun on shore fires a shot at a ship which is heading directly towards the gun at a speed of 40 km/h. At instant of firing,the distance to the ship is 15000 m . The muzzle speed of the shot is 700 m/s.pretend that there is no air resistance.(A)What is the required elevation angle for the gun ?Assume g=9.8 m/s^2 (B)what is the time interval between firing and impact?

An archer pulls the string of her bow back with her hand with a force of 180N.If the two halves of the string above and below her hand make an angle of 120 degree with each other,what is the tension in each half of the string?

A speeding car is travelling at a constant speed of 25m/s when it passes a stopped Car. If the police are accelerates at 6m/s squared how far will the police car have travelled when it catches the speeding car

A wind is blowing at 50 km h−1
from a direction 45° west of north. The pilot of an airplane wishes to fly on
a route due north from an airport. The airspeed of the airplane is 250 km h−1
.
(a)In what direction must the pilot point the nose of the airplane?
(b) What will be the airplane’s speed relative to the ground?

A gun standing on sloping ground (see the figure below) fires up the slope. Show that the slant
range of the gun (measured along the slope) is
l =(2u*2cos*2θ/g cos α)(tan θ − tan α).
Here u is the magnitude of the initial velocity of the bullet

The muzzle speed for a Lee–Enfield rifle is 630 m s−1
. Suppose you fire this rifle at a target 700 m away and
at the same level as the rifle.
(a) In order to hit the target, you must aim at the barrel at a point above the target. How many
meters above the target must you aim? Pretend there is no air resistance.
(b) What will be the maximum height that the bullet reaches along its trajectory?
(c) How long does the bullet take to reach the target?

A stunt driver wants to make his car jump over 10 cars parked side by side below a horizontal
ramp. With what minimum speed must he drive off the ramp? The vertical height of
the ramp is 2.0 m, and the horizontal distance he must clear is 24 m.

A screw jack whose pitch is 22mm is used to raise a motor car of mass 900kg through a height of 20.0cm the lenght of the tommy bar of the jack is 60% efficient calculate the velocity ratio,mechanical advantage of the Jack, effort required, wordone by

A boy stands at the top of the building, with height h above the ground and throws a ball. The ball lands 30m from the building at an angle of 60degrees with respect to the horizontal ground after 2.3s .
A. Find the height of the building.
B. Find the initial velocity at which the ball is thrown and its angle of projection.
C. What is the maximum height rwach by the ball?

What is radioactivity? State its types.