Answer: 56.72 ft/s
Explanation:
Ok, initially we only have potential energy, that is equal to:
U =m*g*h
where g is the gravitational acceleration, m the mass and h the height.
h = 50ft and g = 32.17 ft/s^2
when the watermelon is near the ground, all the potential energy is transformed into kinetic energy, and the kinetic energy can be written as:
K = (1/2)*m*v^2
where v is the velocity.
Then we have:
K = U
m*g*h = (m/2)*v^2
we solve it for v.
v = √(2g*h) = √(2*32.17*50) ft/s = 56.72 ft/s
Answer:
2.86×10⁻¹⁸ seconds
Explanation:
Applying,
P = VI................ Equation 1
Where P = Power, V = Voltage, I = Current.
make I the subject of the equation
I = P/V................ Equation 2
From the question,
Given: P = 0.414 W, V = 1.50 V
Substitute into equation 2
I = 0.414/1.50
I = 0.276 A
Also,
Q = It............... Equation 3
Where Q = amount of charge, t = time
make t the subject of the equation
t = Q/I.................. Equation 4
From the question,
4.931020 electrons has a charge of (4.931020×1.6020×10⁻¹⁹) coulombs
Q = 7.899×10⁻¹⁹ C
Substitute these value into equation 4
t = 7.899×10⁻¹⁹/0.276
t = 2.86×10⁻¹⁸ seconds
Average speed is the ratio of total distance moved by Chi in total time interval
So here we will have
Total distance = 100 m + 400 m
Total time taken = 5 min + 15 min = 20 min
now by the formula of average speed we know that
so average speed will be 1.5 km/h
Answer:
The speed of the ambulance is 4.30 m/s
Explanation:
Given:
Frequency of the ambulance, f = 1790 Hz
Frequency at the cyclist, f' = 1780 Hz
Speed of the cyclist, v₀ = 2.36 m/s
let the velocity of the ambulance be 'vₓ'
Now,
the Doppler effect is given as:
where, v is the speed of sound
since the ambulance is moving towards the cyclist. thus, the sign will be positive
thus,
on substituting the values, we get
or
vₓ = 4.30 m/s
Hence, <u>the speed of the ambulance is 4.30 m/s</u>
It would be the first option.
Explanation-
The number of protons is equal to the atomic number the number of neutrons is the mass minus the atomic number.
