M = mass of the girl = 53.4 kg
m = mass of skateboard = 3.55 kg
V' = velocity of the combination of girl and skateboard before she jumps forward = 0 
V = velocity of the girl forward = 1.32
v = velocity of the skateboard afterward = ?
Using conservation of momentum
(M + m) V' = MV + m v
inserting the values
(53.4 + 3.55) (0) = (53.4) (1.32) + (3.55) v
v = - 19.86
Answer:
Wg is positive and WT negative.
(Letters in options are all wrongly written).
Explanation:
Remember that the work of a force is the internal product between the force and the displacement 
.
Since the displacement is downwards like the weight, the work done by gravity is positive, while the work done by the tension is negative since it points upwards.
Answer:
a. water
Explanation:
A buoy is a floating object that is used in the sea to locate some point or as a checkpoint. It stays at its designated position in the sea by means of an anchor chain. This chain is made short in length according to the water depth do the buoy can not deviate much from its position. The same mechanism can be applied to the metal ion. When a metal ion is formed it remains at its place, but the electrons are mobile and they travel when they get a medium. For example in circuits or from one atom to other. And for the case of buoy, the water serves as electrons as the water is moving in the medium. Hence, the second analogy will be:
electrons : water
So, the correct option is:
<u>a. water</u>
C. Series
Consider resistors in a circuit - if all the resistors in the circuit are in series and one of the resistors fails then no current can flow thru the circuit,
If the resistors are in parallel then then each resistor experiences the same voltage drop regardless of whether or not any resistor in particular is carrying current.
