Physics Answers

A 1.0 kg object is brought to planet Mercury (g = 3.7 m/s/s). where the acceleration due to gravity is 0.38 times its value on Earth.

A target in a shooting board consists of a vertical square wooden board, 0.250 m on a side and with a mass 750 g and pivots around a horizontal axis along its top edge. The board is stuck face-on at its center by a bullet of mass 1.90 g, travelling at 360 m/s that remains embedded in the board.

(a) (2 marks) What is the angular speed of the board just after the bullet’s impact?

(b) (2 marks) What maximum height does the center of the board reach from the equilibrium before it starts swinging down again?

(c) (2 marks) What minimum bullet speed is needed for the board to swing all the way over after the impact?

A target in a shooting board consists of a vertical square wooden board, 0.250 m on a side and with a mass 0.750 g and pivots around a horizontal axis along its top edge. The board is stuck face-on at its center by a bullet of mass 1.90 g, travelling at 360 m/s that remains embedded in the board.

a) (2 marks) What is the angular speed of the board just after the bullet’s impact?

(b) (2 marks) What maximum height does the center of the board reach from the equilibrium before it starts swinging down again?

(c) (2 marks) What minimum bullet speed is needed for the board to swing all the way over after the impact?

The relationship between kinetic energy of an object and the work done by the force(s) acting on it, called the work–kinetic energy theorem, is expressed formally as:

"\\Delta"K ≡ K - K₀ = W

Why is this symbol ( ≡ ) used in the first part of the equation above? Why ( = ) is not used?

Please give full explanation about ≡ and why it is used here and in which situations it is used.

A loop of area 8.0cm is in constant magnetic field of B 0.15 T what is the magnetic flux through the loop when the loop is perendicular to the field?

x * (dy)/(dx) = x ^ 2 + 5y

3 d^ 2 y dx^ 2 + dy dx -14y=0;y(0)=1,y^ prime (0)= -1

Why the speed of sound in water is more than mercury, though the density of mercury is more than water?

A ball was kicked at an angle of 15 degree above the horizontal. The speed is 30 m/s at horizontal dimension (initial). Neglecting air resistance, the projectile will travel at what horizontal distance before striking the ground? Hint: Find first the time before its strikes the ground. Bonus: Get the time as it reaches its peak, the maximum height.

What element is formed by the radioactive decay of (a) ( ) 24 11 − Na  ; (b) ( ) 22 11 + Na  ; (c) ( ) 210 15 P  ?