A
170 g hockey puck sliding at 25 m/s slows to a speed of 10 m/s in a distance of
7.5 m. determine the force of friction
causing the puck to slow.

From 2nd Newton Law:
F=ma
m=170g=0,17kg
Acceleration using kinematic equations:
vk²=vp²+2aΔd
vp-initial velocity=25m/s
vk-ending velocity=10m/s
Δd-distance
a=
a=
a=
a=-35²
F=0,17kg*(-35m/s²)=-5,95N

Answer: it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.explanation:   we have equation of motion ,where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.average velocity = displacement/ time taken.average velocity = 10.69 miles/hr = 10.69*1.6*1000/(60*60) = 4.75 m/s4.75 = s/ts = 4. 1we also have acceleration = 2.18 m/s², initial velocity = 0 m/sso it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.