This is a problem of conservation of momentum
Momentum before throwing the rock: m*V = 96.0 kg * 0.480 m/s = 46.08 N*s
A) man throws the rock forward
=>
rock:
m1 = 0.310 kg
V1 = 14.5 m/s, in the same direction of the sled with the man
sled and man:
m2 = 96 kg - 0.310 kg = 95.69 kg
v2 = ?
Conservation of momentum:
momentum before throw = momentum after throw
46.08N*s = 0.310kg*14.5m/s + 95.69kg*v2
=> v2 = [46.08 N*s - 0.310*14.5N*s ] / 95.69 kg = 0.434 m/s
B) man throws the rock backward
this changes the sign of the velocity, v2 = -14.5 m/s
46.08N*s = - 0.310kg*14.5m/s + 95.69kg*v2
v2 = [46.08 N*s + 0.310*14.5 N*s] / 95.69 k = 0.529 m/s
<h3>
Answer: True</h3>
For example, a very dense metal will sink to the bottom while something like wood will float on the surface. The wood is less dense compared to the water, which is why it floats. Density is the measure of how much stuff you can pack in a certain volume. The higher the density, the more stuff per volume. Think of it like packing a suitcase. If there's barely anything in there, then we can say its density is low. The more stuff crammed in the suitcase will increase the density (and therefore the weight), while keeping the volume the same.
