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3 years ago

Effieiency of simple machine is always less than 100% why

Physics

1 answer:

zysi [14]3 years ago

8 0

Answer:

efficiency of a machine is less than 100% because some part is energy is utilized to overcome some opposing forces like friction which is wasted as heat ,sound energy etc

Explanation:

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A baseball is hit nearly straight up into the air with a speed of 22 m/s. (a) how high does it go ?

AnnZ [28]

So, this is a problem where the accleration is not provided, since it is implied. The only acceleration is acceleration due to gravity (9.8 m/s)

The equation we will use for this problem is $V^2 =V_{0}^2 + 2a (X-X_0)$

V is the final velocity, V₀ is the initial velocity, a is the acceleration, X is the final height, and X₀ is the starting height.

We can assume that the ball starts on the ground since no height is given, so now we plug our numbers in.

We will use 0 as the final velocity, since the ball will stop moving upwards when it is the highest. We will use -9.8 since that is the acceleration due to gravity and we will use 22m/s as V₀ since that is the starting velocity.

$V^2 =V_{0}^2 + 2a (X-X_0)\\0^2 = 22^2 + 2\times-9.8(X-0)\\0=484-19.6x\\-484=-19.6x\\24.69387755 = x\\x\approx24.69$

So, the ball will go 24.69 meters up

4 0

3 years ago

A 200N force pushes forward on the 20kg truck. The truck pulls two crates connected together by ropes, as shown. The gravitation

devlian [24]

Force on left crate, right crate and truck we need to draw here

First we will write the equation for left crate

$T_{left} = m*a$

$T_{left} = 20*a$

Now similarly for right crate

$T_{right} - T_{left} = 20*a$

now for truck

$F - T_{right} = 20*a$

Now we know that F = 200 N

$200 - T_{right} = 20*a$

now add all three equation

$T_{left} + T_{right} - T_{left} + 200 - T{right} = 20a + 20 a + 20a$

$200 = 60 a$

$a = 10/3 m/s^2$

now we will find all tension using this value of acceleration

$T_{left} = 20 * \frac{10}{3} = \frac{200}{3} N$

$T_{right} - \frac{200}{3} = 20*\frac{10}{3}$

$T_{right} = \frac{400}{3} N$

6 0

3 years ago

A 15 m ladder with a mass of 51 kg is leaning against a frictionless wall, which makes an angle of 60 degrees with the horizonta

timofeeve [1]

Answer:

Explanation:

Given that, .

Mass of ladder is 51kg

Then, it weight is

WL = mg = 51 × 9.81 = 500.31N

This weight will act at the midpoint of the ladder

Length of ladder is 15m

The ladder makes an angle 55°C with the horizontal

An object whose mass is 81kg is at 4m from the bottom of the ladder

Then, weight of object

Wo = mg = 81 × 9.81 = 794.61 N

Using newton second law

Check attachment

Ng is normal force on the ground

Ff is the horizontal frictional force

Nw Is the normal force on the wall

ΣFy = 0

Ng = Wo + WL

Ng = 794.61 + 500.31

Ng = 1294.92 N

Also

ΣFx = 0

Ff — Nw = 0

Then,

Ff = Nw

Now taking moment about point A.

Check attachment

using the principle of equilibrium

Sum of clockwise moment equals to sum of anti-clockwise moment

Also note that the Normal force on the wall is not perpendicular to the ladder, so we will resolve that and also the weights of ladder and weight of object

Clockwise = Anticlockwise

Wo•Cos60 × 4 + WL•Cos60 × 7.5 = Nw•Sin60 × 15

794.61Cos60 × 4 + 500.31Cos60 × 7.5 = Nw × Sin60 × 15

1589.22 + 1876.163 = 12.99•Nw

3465.383 = 12.99•Nw

Nw = 3465.383 / 12.99

Nw = 266.77 N

Since, Nw = Ff

Then, Ff = 266.77N

the horizontal force exerted by the ground on the ladder is 266.77 N