Speed = distance / time
S= 40 000m / 5400s
S= 7.41m/s
Matter that emits no light at any wavelength is called DARK MATTER.
Answer:
Electric force, 
Explanation:
Given that,
Electric charge 1, 
Electric charge 2, 
Distance, 
To find,
The electric force between these two sets of charges.
Solution,
There exists a force between two electric charges and this force is called electrostatic force. It is equal to the product of electric charged divided by square of distance between them.

k is the electrostatic constant


So, the electric force between these two sets of charges is
.
The time that the car take to catch up to truck would be :
1/2 ar^2 = vt
1/2 (3) t^2 = 15t
1.5 t^2 = 15t
t ^2 = 10s
Hope this helps
Answer:
Explanation:
The greatest speed is attained at middle point or equilibrium point or where displacement from equilibrium point is zero .
When the object remains at one of the extreme point it experiences greatest acceleration but at that point velocity is zero . Due to acceleration , its velocity goes on increasing till it come to equilibrium point . At this point acceleration becomes zero . After that its velocity starts decreasing because of negative acceleration . Hence at middle point velocity is maximum .
The greatest acceleration is attained at maximum displacement or at one of the two extreme end .
Greatest restoring force too will be at position where acceleration is maximum because acceleration is produced by restoring force .
Restoring force is proportional to displacement or extension against restoring force . So it will be maximum when displacement is maximum .
Zero restoring force exists at equilibrium position or middle point or at point where displacement is zero . It is so because acceleration at that point is zero .