Answer: The principle of conservation of energy, angular speed and centripetal force
Explanation:
At point A, the car experienced maximum of potential energy
As it moves down the hill, the potential energy decreases while the kinetic energy increases.
The maximum kinetic energy of the car is needed for the attainment of enough centripetal force to help the car move through the loop without falling .
Answer:
Option D is correct: 170 µW/m²
Explanation:
Given that,
Frequency f = 800kHz
Distance d = 2.7km = 2700m
Electric field Eo = 0.36V/m
Intensity of radio signal
The intensity of radial signal is given as
I = c•εo•Eo²/2
Where c is speed of light
c = 3×10^8m/s
εo = 8.85 × 10^-12 C²/Nm²
I = 3×10^8 × 8.85×10^-12 × 0.36²/2
I = 1.72 × 10^-4W/m²
I = 172 × 10^-6 W/m²
I = 172 µW/m²
Then, the intensity of the radio wave at that point is approximately 170 µW/m²
Answer:
Explanation:
Given
mass of book(m)=2.1 kg
height up to which book is lifted is (h)2.2 m
height of person 
Potential energy of book relative to ground=mgh
(b)PE w.r.t to person head =mg(h-h0)
work done by person in lifting box 2.2 m w.r.t floor
Word done =Potential Energy of box relative to floor=45.2 J
Given Information:
Initial speed = u = 3.21 yards/s
Acceleration = α = 1.71 yards/s²
Final speed = v = 7.54 yards/s
Required Information:
Distance = s = ?
Answer:
Distance = s = 13.61
Explanation:
We are given the speeds and acceleration of the runner and we want to find out how much distance he covered before being tackled.
We know from the equations of motion,
v² = u² + 2αs
Where u is the initial speed of the runner, v is the final speed of the runner, α is the acceleration of the runner and s is the distance traveled by the runner.
Re-arranging the above equation for distance yields,
2αs = v² - u²
s = (v² - u²)/2α
s = (7.54² - 3.21²)/2×1.71
s = 46.55/3.42
s = 13.61 yards
Therefore, the runner traveled a distance of 13.61 yards before being tackled.
It's not possible to answer the question exactly the way it's written.
That's because we don't know anything about the direction they
drive at any time during the trip.
You see, "velocity" is not just a word that you use for 'speed' when
you want to sound smart and technical, like this question is doing.
"Velocity" is a quantity that's made up of speed AND THE DIRECTION
of the motion. If you don't know the direction of the motion, then you
CAN'T tell the velocity, only the speed.
Here are the average speeds that Lori's family drove on each leg
of their trip:
Speed = (distance covered) / (time to cover the distance) .
Leg-A:
Speed = 15km/10min = 1.5 km/min
Leg-B:
Speed = 20km/15min = (1 and 1/3) km/min
Leg-C
Speed = 24km/12min = 2 km/min
Leg-D:
Speed = 36km/9min = 4 km/min
Leg-E:
Speed = 14km/14min = 1 km/min
From lowest speed to highest speed, they line up like this:
[Leg-E] ==> [Leg-B] ==> [Leg-A] ==> [Leg-C] ==> [Leg-D]
1.0 . . . . . . . . 1.3 . . . . . . . 1.5 . . . . . . . 2.0 . . . . . . . 4.0 . . . . km/minute
Whoever drove Leg-D should have been roundly chastised
and then abandoned by the rest of the family. 36 km in 9 minutes
(4 km per minute) is just about 149 miles per hour !
