Construct a vector diagram. It will be a right-angled triangle. One vector (the hypotenuse) represents the heading of the boat, one represents the current and one represents the resultant speed of the boat, which I'll call x. Their magnitudes are 20, 3 and x. Let the required angle = theta. We have:
<span>theta = arcsin(3/20) = approx. 8.63° </span>
<span>The boat should head against the current in a direction approx. 8.63° to the line connecting the dock with the point opposite, or approx. 81.37° to the shore line. </span>
<span>x = sqrt(20^2 - 3^2) </span>
<span>= sqrt(400 - 9) </span>
<span>= sqrt 391 </span>
<span>The boat's crossing time = </span>
<span>0.5 km/(sqrt 391 km/hr) </span>
<span>= (0.5/sqrt 391) hr </span>
<span>= approx. 0.025 hr </span>
<span>= approx. 91 seconds</span>
By the law of momentum conservation:-
=>m¹u¹ + m²u² = m1v1 + m²v² {let East is +ve}
=>u¹ + u² = v¹ + v² {as m1=m2}
=>3.5 - 2.75 = v1-1.5
<span>
=>v¹ = 2.25 m/s (East) </span>
Answer:
The difference in the length of the bridge is 0.42 m.
Explanation:
Given that,
Length = 1000 m
Winter temperature = 0°C
Summer temperature = 40°C
Coefficient of thermal expansion 
We need to calculate the difference in the length of the bridge
Using formula of the difference in the length
Where, 
= temperature difference
=Coefficient of thermal expansion
L= length
Put the value into the formula
Hence, The difference in the length of the bridge is 0.42 m.
Answer:
Sound waves are produced when something vibrates.
Explanation:
The vibrating body causes the medium (water, air, etc.) Vibrations in air are called traveling longitudinal waves, which we can hear. Sound waves consist of areas of high and low pressure called compressions and rarefactions, respectively.
Sorry if this if wrong
Answer:
<h3>The answer is 12 m/s²</h3>
Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
f is the force
m is the mass
From the question we have
We have the final answer as
<h3>12 m/s²</h3>
Hope this helps you
