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3 years ago

When t= 1 a stone B is thrown vertically upwards from ground level with speed 5ms (ii) find t when a and b collide

Physics

1 answer:

Ksju [112]3 years ago

5 0

Answer:

i don't know if this is good for you but

Explanation:

ignoring frictional air resistance (drag) the speed on return is the same as when it left the ground (5 m/s but in the opposite direction).

Note: this points out a good reason for not firing live bullets into the air..they will return somewhere and at the same speed.

However, if you take into account the atmospheric drag the reurn speed will be somewhat smaller (but in the case of a bullet, probably still lethal.) Drag depends on many factors and is difficult to calculate.

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What in the world is infrared radiation

alexandr402 [8]

Infrared radiation is heat that travels from one place to another
in the form of electromagnetic waves.

It's called "infrared" because its wavelength is just past the
longest visible light ... the next category with wavelengths
longer than red light.

Infrared radiation is how heat gets here from the sun, and how
you feel the heat from a fireplace or a campfire when you stand
20 feet away from them. When that happens, your front gets
toasty while your back stays cold, so you know it's not a matter
of any warm air around you that's warming you. It's the infrared
electromagnetic radiation direct from the fire to your skin.

7 0

3 years ago

Calculate the initial speed of a box which slides on a horizontal floor surface and comes to rest after sliding 2 s. The coeffic

NARA [144]

A box sliding on a horizontal floor surface starts out moving at 4.9 m/s and stops after 2 seconds. The surface and the box have a kinetic friction has friction coefficient of 0.25 (g=9.8 ms-2).

The speed of an object at the start of a measurement, or an initial state, is known as the initial speed. The ratio of distance travelled to travel time, also known as the average speed, is the sum of the initial and final speeds. The difference between initial and ending speeds is the speed change. A force that acts between moving surfaces is referred to as kinetic friction. A force acting in opposition to the direction of a moving body on the surface is felt.

Interval (t) equals 2 seconds

Kinetic friction coefficient is 0.25.

gravity-induced acceleration (g) = 9.8 m/s2.

Coming to a stop at a final velocity of 0 m/s.

Regular force equals mg

Kinetic friction force is given by = k.

N = μkmg

I = (delta P) (delta P)

Vo = (0.25)(9.8)(2) (2)

Vo = 4.9m/s

Learn more about kinetic friction here

brainly.com/question/17237604

#SPJ4

3 0

1 year ago

Which of the following has the greatest momentum? *

denis-greek [22]

Answer:

Tortoise with a mass of 270 kg moving at a velocity of 0.5 m/s

Explanation:

From the question above,

(1) tortoise with a mass of 270 kg moving at a velocity of 0.5 m/s

Mometum = mass×velocity

Momentum = 270×0.5

Momentum = 135 kgm/s

(2) hare with a mass of 2.7 kg moving at a velocity of 7 m/s

Mementum = mass × velocity

Momentum = 2.7×7

Momentum = 18.9 kgm/s

(3) turtle with a mass of 91 kg moving at a velocity of 1.4 m/s

Momentum = mass × velocity

Momentum = 91×1.4

Momentum = 127.4 kgm/s

(4) roadrunner with a mass of 1.8 kg moving at a velocity of 6.7 m/s

Momentum = mass × velocity

Momentum = 1.8×6.7

Momentum = 12.06 kgm/s

From the above, the one with the greatest momentum is tortoise with a mass of 270 kg moving at a velocity of 0.5 m/s

3 0

3 years ago

A low orbit satellite at 100 km altitude had a camera that resolved a car location to within 0.3 meter. Find the minimum diamete

NeX [460]

Answer:

Minimum diameter of the camera lens is 22.4 cm

The focal length of the camera's lens is 300cm

Explanation:

y = Resolve distance = 0.3 m

h = Height of satellite = 100 km

λ = Wavelength = 550 nm

Angular resolution

$tan\theta\approx \theta =\frac{y}{h}\\\Rightarrow \theta=\frac{0.3}{100\times 10^3}=3\times 10^{-6}$

From Rayleigh criteria

$sin\theta=1.22\frac{\lambda}{D}\\\Rightarrow D=1.22\frac{\lambda}{sin\theta}\\\Rightarrow D=1.22\frac{550\times 10^{-9}}{sin3\times 10^{-6}}=0.2236\ m=22.4\ cm$

Minimum diameter of the camera lens is 22.4 cm

Relation between resolvable feature, focal length and angular resolution

$d=f\Delta \theta\\\Rightarrow f=\frac{d}{\Delta \theta}\\\Rightarrow f=\frac{9\times 10^{-6}}{3\times 10^{-6}}=3\ m=300\ cm$

The focal length of the camera's lens is 300cm

3 0

3 years ago

Marie is puzzled by her findings she has done several meticulous calculations and has gotten the numbers .37 rad, .89 rad and 1.

Irina-Kira [14]

Answer:

I think the answer is a

Explanation:

for it to be accurate has be to exactly 0.9 rad

it is not precise because the answer she is getting is different everytime and not even close. For instance,

It would have been precise if she had gotten 0.37 rad in every attempt. or 0.89 every attempt...

6 0

3 years ago