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2 years ago

6

A cricket ball is dropped from a height of 20 m. Calculate: a) the speed of the ball. b) the time it takes to fall through this

height

1 answer:

AysviL [449]2 years ago

7 0

Answer:

Initial velocity is 0 .. ( since it is just dropped)

now using V²= u² +2gh

=> (Vfinal)² = 0+2*10*20

=> v² = 20*20 = 400

=> v = √400 = 20m/s

for time taken

use V = u+gt

=> t = V/g = 20/10 = 2sec

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Moustapha jones drives east at 100km/hr for 3 hours then back west at 80km/hr for 1.5 hours. which pair of answers gives his ave

olya-2409 [2.1K]

The average speed of the car is 93.33 km/hr and the average velocity of the car is 40 km/hr.

The total distance cover in east direction is=100*3=300 km

The total distance cover in the west direction=80*1.5=120 km

The total distance covered is =300+120=420 km

And Total displacement of the car is =300-120=180 km

As we know that the average speed is given as

Avg Speed =Total Distance / Total time

=420/4.5=93.33 km/hr

As we know that the average velocity is given as

Avg Speed =Total Displacement/ Total time

=180/4.5=40 km/hr

Therefore, The average speed of the car is 93.33 km/hr and the average velocity of the car is 40 km/hr.

7 0

3 years ago

What is an example of a form of friction that impedes motion

Travka [436]

Answer:

to me I think is static

Explanation:

that is my own thinking

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2 years ago

A cubic sample of a new kind of artificial tissue is subject to an increase in pressure of 160 kPa which results in a reduction

grin007 [14]

Answer:

0.82 MPa

Explanation:

the change in pressure 'σ'=160kPa

K= σ/∈ $Ф_v$ => σ/3∈ $Ф_L$

K= 160/(3 x 0.065)

K=820 kPA=0.82 MPa

Thus,the bulk modulus of the tissue 'K' is 0.82 MPa

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2 years ago

1. thomas jefferson proposed using the length (l) of a simple pendulum whose period (t) was exactly 2 seconds as the definition

Alecsey [184]

The length of a 2 sec pendulum is 1 m.

Given that, initial length of the simple pendulum L₁ = 1 m

Initial time period T₁ = 2 sec

We need to find the length of the pendulum whose time period is 2 sec

T₂ = 2 sec

L₂ = ?

We know that the time period of the simple pendulum is given by the formula,

T = 2π√(L/g)

From the above relation, we can write T ∝ √L

T₁ / T₂ = √(L₁/L₂)

Making L₂ from the above relation, we have,

L₂ = (T₂² * L₁)/ T₁² = 2² * 1/ 2² = 1 m

Thus, the length of a 2 sec pendulum is 1 m.

To know more about time period:

brainly.com/question/17350379

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1 year ago

Astronaut Sarah leaves Earth in a spaceship at a speed of 0.280c relative to Earth. Sarah's destination is a star-system 12.5 li

Usimov [2.4K]

Answer:

L= 12 light years

Explanation:

for length dilation we use the formula

$L=L_0\sqrt{1-\frac{v^2}{c^2} }$

now calculating Lo

Lo = 12.5×365×24×3600×3×10^8

= 1.183×10^17 m

now putting the values of v and Lo in the above equation we get

$L=1.183\times10^{17}\sqrt{1-\frac{0.28c^2}{c^2} }$

= 1.136×10^17 m

L= $= \frac{1.136\times10^{17}}{365\times24\times3600\times3\times10^8}$ m

so L= 12 light years

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3 years ago