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Westkost [7]
3 years ago
9

A force of 70 N is applied to a 28 kg rock causing it to slow down from 25 m/s to 15 m/s, a change in velocity of 10 m/s. How lo

ng was that force applied?
Physics
1 answer:
maksim [4K]3 years ago
7 0

Answer: 4 s

Explanation:

Given

The applied force is 70 N

mass of the rock is 28 kg

initial velocity u=25\ m/s

final velocity v=15\ m/s

Deceleration provided by force is

a=-\dfrac{70}{28}=-2.5\ m/s^2

using the equation of motion

v=u+at\\\Rightarrow 15=25-2.5t\\\Rightarrow 2.5t=10\\\Rightarrow t=4\ s

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For the airfoil and conditions in Problem 2.2, calculate the lift-to-drag ratio. Comment on its magnitude.
raketka [301]

Answer:

L/D= 112

Explanation:

Aerodynamics can be defined as the branch of dynamics which deals with the motion of air, their properties and the interaction between the air and solid bodies.

Aerodynamics law explains how an airplane is able to fly. There are four forces of flight, and they are; lift, weight, thrust and drag. The amount of lift generated by a wing divided by the aerodynamic drag is known as the lift to drag ratio.

Lift increases proportionally to the square of the speed.

The solutions to the question is the file attached to this explanation.

Lift,L= qC(l). S---------------------------(1).

and,

Drag,D = qC(d).S ----------------------(2).

Hence, Lift to drag ratio,L/D= C(l)/C(d).

Therefore, we have to compute various angle of attack.(check attached file)...

Then, (L/D) will then be equal to 112.

8 0
3 years ago
A 12.0 g sample of gas occupies 19.2 L at STP. what is the of moles and molecular weight of this gas?​
lubasha [3.4K]

At STP, 1 mole of an ideal gas occupies a volume of about 22.4 L. So if <em>n</em> is the number of moles of this gas, then

<em>n</em> / (19.2 L) = (1 mole) / (22.4 L)   ==>   <em>n</em> = (19.2 L•mole) / (22.4 L) ≈ 0.857 mol

If the sample has a mass of 12.0 g, then its molecular weight is

(12.0 g) / <em>n</em> ≈ 14.0 g/mol

4 0
2 years ago
Explain the process of synaptic transmission, beginning with the neurotransmitters at the axon terminal of the presynaptic cell
nydimaria [60]

The synapse is actually the link between 2 neurons. Now when an action potential contacts the synaptic knob of a neuron, the voltage-gate calcium channels are unlocked, resulting in an influx of positively charged calcium ions into the cell. This makes the vesicles containing neurotransmitters, for example acetylcholine, to travel towards the pre-synaptic membrane. When the vesicle arrives at the membrane, the contents are released into the synaptic cleft by exocytosis. Neurotransmitters disperse across the space, down to its concentration gradient, up until it reaches the post-synaptic membrane, where it connects to the correct neuroreceptors. Connecting to the neuroreceptors results in depolarisation in the post-syanaptic neuron as voltage-gated sodium channels are also opened, and the positively charged sodium ions travel into the cell. When adequate neurotransmitters bind to neuroreceptors, the post-synaptic membrane overcame the threshold level of depolarisation and an action potential is made and the impulse is transmitted.

8 0
3 years ago
Read 2 more answers
A light wave has a wavelength of 450 nanometers. What is the frequency of this light?
Zolol [24]

Answer:

Frequency, f=6.67\times 10^{14}\ Hz

Explanation:

Wavelength of a light wave is 450 nm. It is required to find the frequency of this light wave. The speed of light is given by c. So,

c=f\lambda

f is the frequency of this light

f=\dfrac{c}{\lambda}\\\\f=\dfrac{3\times 10^8}{450\times 10^{-9}}\\\\f=6.67\times 10^{14}\ Hz

So, the frequency of this light is 6.67\times 10^{14}\ Hz.

3 0
3 years ago
A circular 10-turn coil with a radius of 5.0 cm carries a current of 5 A. It lies in the xy plane in a uniform magnetic field =
Tju [1.3M]

Answer:

U = – 0.12J

Explanation:

Given N = 10 turns, I = 5A, r = 5×10-²m

B^ = 0.05 T iˆ+ 0.3 T kˆ

Magnitude of the magnetic field vector B = √(0.05²+0.3²) = 0.304T

Area = πr² = π(5×10-²)² = 7.85×10-³m²

Magnetic moment μ = NIA

μ = 10×5×7.85×10-³ = 0.3925Am²

U = -μ•B = –0.3925×0.304 = –0.12J

The sign is negative because the magnetic moment is aligned with the magnetic field.

3 0
3 years ago
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