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3 years ago

A bag is dropped onto the street from the roof of a 32 m high building. How long does it take for the bag to fall?

Physics

1 answer:

gizmo_the_mogwai [7]3 years ago

4 0

Answer:

Explanation:

h = ½at²

t = √(2h/a)

t = √(2(32)/9.8)

t = 2.5555062... 2.6 s

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A bullet with a mass m b = 11.9 mb=11.9 g is fired into a block of wood at velocity v b = 261 m/s. vb=261 m/s. The block is atta

fredd [130]

Answer:

0.372 kg

Explanation:

The collision between the bullet and the block is inelastic, so only the total momentum of the system is conserved. So we can write:

$mu=(M+m)v$ (1)

where

$m=11.9 g = 11.9\cdot 10^{-3}kg$ is the mass of the bullet

$u=261 m/s$ is the initial velocity of the bullet

$M$ is the mass of the block

$v$ is the velocity at which the bullet and the block travels after the collision

We also know that the block is attached to a spring, and that the surface over which the block slides after the collision is frictionless. This means that the energy is conserved: so, the total kinetic energy of the block+bullet system just after the collision will entirely convert into elastic potential energy of the spring when the system comes to rest. So we can write

$\frac{1}{2}(M+m)v^2 = \frac{1}{2}kx^2$ (2)

where

k = 205 N/m is the spring constant

x = 35.0 cm = 0.35 m is the compression of the spring

From eq(1) we get

$v=\frac{mu}{M+m}$

And substituting into eq(2), we can solve to find the mass of the block:

$(M+m) \frac{(mu)^2}{(M+m)^2}=kx^2\\\frac{(mu)^2}{M+m}=kx^2\\M+m=\frac{(mu)^2}{kx^2}\\M=\frac{(mu)^2}{kx^2}-m=\frac{(11.9\cdot 10^{-3}\cdot 261)^2}{(205)(0.35)^2}-11.9\cdot 10^{-3}=0.372 kg$

4 0

3 years ago

If energy cannot be created or destroyed, where does it go?

blondinia [14]

It transfers and changes into different types of energy, this is why the ground feels hot when something moves fast over it.

3 0

3 years ago

Read 2 more answers

in a car moving at constant acceleration, you travel 230 mm between the instants at which the speedometer reads 40 km/hkm/h and

Ronch [10]

The acceleration of the car is 0.8049 $m/s^{2}$ .It takes 13.802s to travel the 230 m.

<h3>What is acceleration?</h3>

In mechanics, acceleration refers to the rate at which an object's velocity with respect to time varies. Acceleration is a vector quantity (in that they have magnitude and direction). The direction of an object's acceleration is determined by the direction of the net force acting on it. Newton's Second Law states that the combined effect of two factors determines how much an item accelerates:

(i) It follows that the magnitude of the net balance of all external forces acting on the object is directly proportional to the magnitude of this net resulting force, and

(ii) the mass of the thing, depending on the materials out of which it is constructed, is inversely proportional to the mass of the thing.

Calculations:

40 km/hr ----- 11.11m/s

80 km/hr ----- 22.22m/s

$v^{2} -u^{2} =2as\\22.22^{2} - 11.11^{2} = 2 x a x 230\\ 370.296=460a\\ a= 0.8049m/s^{2} \\$

Time taken

v-u=at

22.22-11.11= 0.8049 x t

t=13.802s

To learn more about acceleration ,visit:

brainly.com/question/2303856

#SPJ4

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1 year ago

what do you think is the purpose of a periscope? Are there any other uses for periscopes besides for submarines?

spin [16.1K]

Military personnel also use periscopes in some gun turrets and in armoured vehicles. More complex periscopes using prisms or advanced fibre optics instead of mirrors and providing magnification operate on submarines and in various fields of science

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3 years ago

Will mark BRAINLIEST!!!!

REY [17]

Answer:

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2 years ago