Yes because it helps them locate their position and direction
False, sharks and remoras have a symbiotic relationship. The remora removes parasites from the sharks scales, and the shark provides protection for the remora
Answer:
Explanation:
Given
Weight of roller coaster is 
mass of roller coaster 
Distance traveled by roller coaster 
drag force 
velocity at top 
Suppose E is the initial energy
Conserving Energy at bottom and top



Answer:
The momentum would be doubled
Explanation:
The magnitude of the momentum of the freight train is given by:

where
m is the mass of the train
v is its speed
In this problem, we have that the speed of the train is unchanged, while the mass of the train is doubled:

therefore, the new momentum is

so, the momentum has also doubled.
Answer:
20 kg
Explanation:
remember the equation f=ma.
100 N=force
5 m/s2= acceleration
so you need to divide force by acceleration: 100 N/ 5 m/s2= 20 kg, to get the mass.