1. A rife is aimed horizontally at a target 100m away. A bullet is fired and lea

Question

1. A rife is aimed horizontally at a target 100m away. A bullet is fired and leaves the barrel with a speed of 400 m/s.

a)What is the bullets flight time?

b) How far below the aim point on the target does the bullet strike?

2.A wooden block slides down a wooden ramp inclined at 60 degree angle. The block has a mass of 3kg and the coefficient of kinetic friction 0.4.

a)Draw a free-body diagram for the block. Include all forces acting on the block (there are 3)

b)Write 2 equations for Newtons second law. Solve for the blocks acceleration.

c) If the ramp is 1 meter long how long will it take for the block to reach the bottom?

3. A 5kg wooden block sits on top of a horizontal wooden table. A string attached to the block goes over a pulley and is attached to a hanging block at the other end. The coefficients off friction is 0.6 and 0.4 the system is at rest.

a)Draw a free body diagram for each block seperatly clearly labeling each force?

b)Write Newtons 2nd law in 2 dimensions for each block (4 equtions)

c) Find the largest hanging mass that will not cause the system to slip?

d) Now assum that you double the mass you found in part c). what will be the acceleration of the system?

Explanation / Answer

1) a) using the equation of motion we have

X = Ux*t

100 = 400*t

t = 0.25 s

b) Y = Uyt - 0.5gt^2

Y = 0 - 0.5*9.8*0.25^2

= -0.3m

so it hit below 0.3 m

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