Let's use ' t ' to represent half of the time, in hours.
The distance traveled in the first half of the time is (80 t) km.
The distance traveled in the last half of the time is (40 t) km.
The total distance covered is (80t + 40t) = (120t) km.
You said that the total distance covered was 60 km,
so ...
120 t = 60 km
Divide each side by 120 : t (half of the time) = 0.5 hour
Average speed = (total distance covered) / (time to cover the distance)
= (60 km) / (1 hour)
= 60 km/hr .
One electron Volt (eV) is equal to 1.6 x 10^-19 Joules. Therefore, 10 eV is equal to 1.6 x 10^-18 Joules. In order to produce 20 Joules of energy from 10 eV photons, we would require 20 x 1/(1.6 x 10^-18) = 1.25 x 10^19 particles. This demonstrates that in the world of particle physics, the Joule is a massive energy unit relative to the commonly used electron Volt.
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>
Answer:
Explanation:
For an electric force, F the formula:
F = kQq/r^2
Given:
r2 = 1/2 × r1
F1 × r1 = k
F1 × r1 = F2 × r2
F2 = (F1 × r1^2)/(0.5 × r1)^2
= (F1 × r1^2)/0.25r1^2
= 4 × F1.
Answer: The minimum acceleration for the air plane is 2.269m/s2.
Explanation: To solve such problem the equation of motion are applicable.
The initial velocity is 0 since the airplane was initially standing. We are going to use this equation
V^2=U^2+2as
33^2=0+2a (240)
a= 2.269m/s2
