A river has a current of 5 m/s. A boat tries to head directly across at 4 m/s. When the boat reaches the other side it is 30m downstream.
How wide is the river ?
how long did it take to get across?
30=5*time
how wide is the river?
W=4t
A 80KG hockey player has a coefficient of friction u=0.08 between her skates and ice. What is the force of friction on the player?
0.08(80 x 9.8)
=62.7N
If the hockey player is coasting, what is the net force?
To find out the width of the river, we need to calculate the time it took for the boat to cross and the distance it traveled downstream during that time.
Let's assume the width of the river is represented by "d."
First, we can calculate the time it took for the boat to cross the river. We can use the formula:
Time = Distance / Speed
The distance the boat travels across the river is "d," and the speed of the boat is 4 m/s. So, the time taken to cross the river is:
Time to cross = d / 4
Next, we need to calculate the distance the boat traveled downstream during that time. We know that the speed of the river's current is 5 m/s, and the time taken to cross the river is "d / 4" seconds. So, the distance traveled downstream is:
Distance downstream = Speed of current × Time to cross
= 5 × (d / 4)
= (5d) / 4
According to the problem, the boat traveled 30 m downstream. Therefore, we can set up the equation:
Distance downstream = 30
(5d) / 4 = 30
To solve for "d," we can multiply both sides of the equation by 4/5:
(5d) / 4 × 4/5 = 30 × 4/5
d = 24
Therefore, the width of the river is 24 meters.