BoogieBot
Oct5-08, 02:30 PM
1. A child pulls a sled with mass 9.0kg through the snow(note: no coefficient of friction given, but there _is_ friction between sled & snow). The sled accelerates at 1.0 m/s2. The rope exerts 27Nt on the sled in the forward direction.
a) what force must the rope exert on the child (magnitude & direction)?
b) What is the magnitude of the frictional force on the sled (hint: it's in the opposite direction of the sled's motion)?
2. Relevant equations
F=ma
3. The attempt at a solution
a) 27 Nt, due to Newton's 3rd law, in the opposite direction of the child/sled's motion.
b)
Frope - Fk = Ftotal = ma
Frope = Fk + ma
27 = Fk + (9 * 1)
18Nt = Fk
are my answers correct? Should their signs be negative, because they are in the opposite direction of the sled's motion? Have I made any glaring omissions regarding the rope's tension?
a) what force must the rope exert on the child (magnitude & direction)?
b) What is the magnitude of the frictional force on the sled (hint: it's in the opposite direction of the sled's motion)?
2. Relevant equations
F=ma
3. The attempt at a solution
a) 27 Nt, due to Newton's 3rd law, in the opposite direction of the child/sled's motion.
b)
Frope - Fk = Ftotal = ma
Frope = Fk + ma
27 = Fk + (9 * 1)
18Nt = Fk
are my answers correct? Should their signs be negative, because they are in the opposite direction of the sled's motion? Have I made any glaring omissions regarding the rope's tension?