I am not entirely sure but i believe the answer is C scupture
1.Density of the material building the raft must be lower than the water.
<span>2. Material must not react with water. </span>
<span>3.Material must have high strength. </span>
<span>4.Raft must be wide in-order to avoid drawing in the river.</span>
Answer: 
Explanation:
This problem can be solved by the following equation:

Where:
is the change in kinetic energy
is the electric potential difference
is the electric charge
Finding
:


Finally:

Answer:
Speed is a scalar quantity that refers to "how fast an object is moving." Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a short amount of time.
Explanation:
The formula for speed is speed = distance ÷ time. To work out what the units are for speed, you need to know the units for distance and time.