Question

# 7. A 77.0 kg ice hockey goalie, originally at rest, catches a 0.150 kg hockey puck...

7. A 77.0 kg ice hockey goalie, originally at rest, catches a 0.150 kg hockey puck slapped at him at a velocity of 34.0 m/s. Suppose the goalie and the ice puck have an elastic collision and the puck is reflected back in the direction from which it came. What would their final velocities (in m/s) be in this case? (Assume the original direction of the ice puck toward the goalie is in the positive direction. Indicate the direction with the sign of your answer.)

puck = -33.86 m/s

goalie = ____ m/s

9. During an ice show a 70.0 kg skater leaps into the air and is caught by an initially stationary 90.0 kg skater.

(a)What is their final velocity in meters per second assuming negligible friction and that the 70.0-kg skater's original horizontal velocity was 4.00 m/s?

1.75 m/s

(b)How much kinetic energy is lost in joules?

___ J

17. The upper leg muscle (quadriceps) exerts a force of

FQ = 1120 N,

which is carried by a tendon over the kneecap (the patella) at the angles shown in the figure below.

Find the magnitude in newtons and direction in degrees counter-clockwise from an axis directed to the left of the force exerted by the kneecap on the upper leg bone (the femur).

Magnitude = ____ N

direction = 10 ° counter-clockwise from an axis directed to the left

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