Answer:
3. 3.5 s
Explanation:
The position of traveller A is given by the equation:

where
is the acceleration of A
t is the time measured from when A started the motion
The position of traveller B instead is given by

where a (acceleration) is the same as traveller A, and

is B's initial velocity. We can verify that the formula is correct by substituting t=2, and we get
, which means that B starts its motion 2 seconds later.
Traveller B overtakes traveller A when the two positions are the same, so:

By definition of average acceleration,
<em>a</em> = (20 m/s - 33.1 m/s) / (4.7 s) ≈ -2.78 m/s²
Vertically, the car is in equilibrium, so the net force is equal to the friction force in the direction opposite the car's motion:
∑ <em>F</em> = (1502.7 kg) (-2.78 m/s²) ≈ -4188.38 N ≈ -4200 N
If you just want the magnitude, drop the negative sign.
Answer:
b. melting
Explanation:
it is made of sediments and that is not necessary