Question

A 0.68 kg block of ice is sliding by you on a very slippery floor at 2.6 m/s. As it goes by, you give it a kick perpendicular to its path. Your foot is in contact with the ice block for 0.0032 seconds. The block eventually slides at an angle of 27 degrees from its original direction (labeled θ in the diagram). The overhead view shown in the diagram is approximately to scale. The arrow represents the average force your toe applies briefly to the block of ice. (a) Which of the possible paths shown in the diagram corresponds to the correct overhead view of the block's path? (b) Which components of the block's momentum are changed by the impulse applied by your foot? (Check all that apply. The diagram shows a top view, looking down on the x⁢z plane.) x component y component z component (c) What is the unit vector in the direction of the block's momentum after the kick? p^= < , , > (d) What is the x component of the block's momentum after the kick? pf⁢x= kg·m/s (e) Remember that p→=|p→|p^ . What is the magnitude of the block's momentum after the kick? |p→|= kg·m/s (f) Use your answers to the preceding questions to find the z component of the block's momentum after the kick (drawing a diagram is helpful). pf⁢z= kg·m/s (g) What was the magnitude of the average force you applied to the block? |F→avg|= N

Answer 1

(a) I think path B is correct (straight line)

(b) x and y component does not change. Only z component will change

(c) <cos 27 , 0 , sin 27>

<0.891, 0 , - 0.4539> (negative sign is because z vector points down)

(d) x component, Px = 0.68 * 2.6 = 1.768 kg.m/s

(e) block's momentum after the kick = 1.768 / cos 27 = 1.984 Kg.m/s

(f) z component = 1.768 * tan 27 = 0.9008 Kg.m/s

(g) we know

force * time = change in momentum

force = 0.9008 / 0.0032= 281.5 N