Answer:
12 cm and 0.4
Explanation:
f = - 20 cm, u = - 30 cm
Let v be the position of image and m be the magnification.
Use lens equation
1 / f = 1 / v - 1 / u
- 1 / 20 = 1 / v + 1 / 30
1 / v = - 5 / 60
v = - 12 cm
m = v / u = - 12 / (-30) = 0.4
1 second - 32m
2 second - 84m
3 second - 156m
4 second - 248m
Hope this helps
I’m pretty sure the answer is 3
Answer:
The reading of the scale during the acceleration is 446.94 N
Explanation:
Given;
the reading of the scale when the elevator is at rest = your weight, w = 600 N
downward acceleration the elevator, a = 2.5 m/s²
The reading of the scale can be found by applying Newton's second law of motion;
the reading of the scale = net force acting on your body
R = mg + m(-a)
The negative sign indicates downward acceleration
R = m(g - a)
where;
R is the reading of the scale which is your apparent weight
m is the mass of your body
g is acceleration due to gravity, = 9.8 m/s²
m = w/g
m = 600 / 9.8
m = 61.225 kg
The reading of the scale is now calculated as;
R = m(g-a)
R = 61.225(9.8 - 2.5)
R = 446.94 N
Therefore, the reading of the scale during the acceleration is 446.94 N
Answer: a) 5 x 10^5 kg/s b) 444 MW
Explanation:
Kinetic energy per unit mass Ke is
Ke = V^2 / 2
Ke = 3^2 / 2 = 4.5 J/kg = 0.0045 kJ/kg
Now potential energy per unit mass Pe is
Pe = g x z = 9.8 x 90 = 882.9 J/kg = 0.8829 kJ/kg
The total mechanical energy of the River per unit mass e = Ke + Pe = 0.0045 + 0.8829 = 0.88744 J/kg
M = P x V = 1000 x 500 = 5 x 10^5 kg/s
b) power generation potential of the entire river at the location Wmax = Emech = M x Emech = 500,000 x 0.88744 = 444,000kW = 444MW