A skateboarder travelling at 10.4

m
s
10.4
s
m

10, point, 4, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction starts getting chased by a grumpy dog. The skateboarder speeds up with a constant acceleration for
39

m
39m39, start text, m, end text over
3.3

s
3.3s3, point, 3, start text, s, end text. We want to find the acceleration of the skateboarder over the
3.3

s
3.3s3, point, 3, start text, s, end text time interval.

Boxing gloves are padded to lessen the force of a blow. (a) calculate the force exerted by a boxing glove on an opponent’s face, if the glove and face compress 7.50 cm during a blow in which the 7.00-kg arm and glove are brought to rest from an initial speed of 10.0 m/s. (b) calculate the force exerted by an identical blow in the gory old days when no gloves were used and the knuckles and face would compress only 2.00 cm. (c) discuss the magnitude of the force with glove on. does it seem high enough to cause damage even though it is lower than the force with no glove?

Two balls, each with a mass of 0.5 kg, collide on a pool table. is the law of conservation of momentum satisfied in the collision? explain why or why not

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.