Answer:
3.49km/hr
Explanation:
This train is moving at 50km/hr
Distance = length of train + distance of tunnel
= 3 km + 40 km
= 43 km
Time taken by train to get to tunnel
Time = distance / velocity
Time = 43 km/50km perhour
= 0.86
How fast will stunt double have to run?
Velocity = 3km/0.86
= 3.49 km/hr
The stunt double will have to run as fast as 3.49 kilometer per hour
According to Georgia State University, gravitational potential energy<span> is the energy an object possesses because of its position in a gravitational field. This is most commonly in reference to an object near the surface of the Earth, where the gravitational acceleration is assumed to be constant at about 9.8 m/s2.</span>
1. The man will be able to move the rock. See diagram.
Moment of Man's force : 400 N * 1.2 meter = 480 N-m
Rock's Weight = 50 Kg * 9.8 m/sec² = 490 Newtons
Moment of Rock's weight : 490 N * 0.80 meters = 392 N-m
<em><u> Moment of Man's Force is MORE : 480 N-m > 392 N-m</u></em><em><u> So man will be able to lift the rock.</u></em>2. Let is look at the diagram - second one.
Let us assume that the fulcrum (Pivot) is placed at X meters from the rock.
So moment of Girl's force about Pivot = 200 N * (2 - X) meters = 400 - 200 X
Moment of Rock's weight = 490 N * X = 490 X
As the Girl is able to lift the rock, 400 - 200 X > 490 X
Hence 400 > 200 X + 490 X
400 > 690 X
X < 400/690 = 0.58 meters
<u>
<em> If the Pivot is placed closer than 0.58 meters or 58 cm to the Rock, then </em></u>
<u>
<em> she can lift the rock.</em></u>
Answer:
Option B. doubles
Explanation:
This can be explained by the definition of capacitance that charge on the capacitor will remain constant irrespective of the voltage applied.
This can be given as:
Q ∝ V or Q = CV
where,
Q = charge
V = Voltage
C = Capacitance
So, when V is doubled, C shoul reduce to half to main constant charge on the capacitor:
V' = 2V
C' =
Also , Energy stored in a capacitor, E is given by:
E = (1)
Now, when
V' = 2V
C' =
Using eqn (1):
E' =
Energy, E' =
E' = = 2E
The letter "B" is used for magnetic field