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3 years ago

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Which statement describes how a machine can help make work easier? It can put out more force than the input force by decreasing

the distance over which force is applied. It can increase the amount of work performed if the output force is in the same direction as the input force. O It can apply a greater output force over a greater distance compared to the input force and distance. It can increase the distance over which output force acts by applying less output force than input force.

1 answer:

Neko [114]3 years ago

7 0

Answer:

it can be

Explanation:

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A ball is hit 1 meter above the ground with an initial speed of 40 m/s. If the ball is hit at an angle of 30 above the horizonta

Vika [28.1K]

Answer:

$t_t=4.131\ s$

Explanation:

Given:

height above the horizontal form where the ball is hit, $y=1\ m$

angle of projectile above the horizontal, $\theta=30^{\circ}$

initial speed of the projectile, $u=40\ m.s^{-1}$

<u>Firstly we find the </u><u>vertical component of the initial velocity</u><u>:</u>

$u_y=u.\sin\theta$

$u_y=40\times \sin30^{\circ}$

$u_y=20\ m.s^{-1}$

During the course of ascend in height of the ball when it reaches the maximum height then its vertical component of the velocity becomes zero.

So final vertical velocity during the course of ascend:

$v_y=0\ m.s^{-1}$

Using eq. of motion:

$v_y^2=u_y^2-2g.h$ (-ve sign means that the direction of velocity is opposite to the direction of acceleration)

$0^2=20^2-2\times 9.8\times h$

$h=20.4082\ m$ (from the height where it is thrown)

<u>Now we find the time taken to ascend to this height:</u>

$v_y=u_y-g.t$

$0=20-9.8t$

$t=2.041\ s$

<u>Time taken to descent the total height:</u>

we've total height, $h'=h+y$ $=20.4082+1$

$h'=u_y'.t'+\frac{1}{2} g.t'^2$

during the course of descend its initial vertical velocity is zero because it is at the top height, so $u_y'=0\ m.s^{-1}$

$21.4082=0+4.9t'^2$

$t'=2.09\ s$

<u>Now the total time taken by the ball to hit the ground:</u>

$t_t=t'+t$

$t_t=2.09+2.041$

$t_t=4.131\ s$

3 0

3 years ago

A student dips a strip of metal into a liquid. Which is evidence that only a physical change has occurred?

sattari [20]

Answer:

PLS add the picture too.....

3 0

3 years ago

A shot putter shoots a 7.3kg shot from rest to 14m/s in 1.5s. what was the average power?

sweet [91]

Answer: 477W

Explanation:

Given the following :

Mass (m) = 7.3kg

Initial Velocity (u) = 0

Final velocity (v) = 14m/s

time (t) = 1.5s

Power = workdone (W) / time (t)

The workdone can be calculated as the change in kinetic energy (KE) :

Recall ;

KE = 0.5mv^2

Therefore, change in KE is given by:

0.5mv^2 - 0.5mu^2

Change in KE = 0.5(7.3)(14^2) - 0.5(7.3)(0^2)

Change in KE = 715.4J

Therefore ;

Average power = Workdone / time

Workdone = change in KE = 715.4N

Average power = 715.4 / 1.5

Average power = 476.93333 W

= 477W

5 0

4 years ago

Two resistors, R1 = 25.0 ohms and

Leni [432]

Answer: 0.078

Explanation:

Given variables:

R1 = 25.0 , R2 = 64.0 , I1 = 0.200

Step 1: find V

0.200 = v/25

0.200 * 25 = v

5 = v

Step 2: Solve for I2

I = V/R

I = 5/64

I = 0.078125

Hope this helps!

3 0

3 years ago

According to which calendar is new year’s celebrated on january 1st?

Sholpan [36]

Answer:

Gregorian calendar

Explanation:

Some types of calendar available are

Gregorian calendar
Julian calendar
Islamic calendar
Solar Hijri calendar
Hebrew calendar

Gregorian calendar: January 1st is new year and it the most widely used calendar in the world.

Julian calendar: January 14th is new year.

Islamic calendar: it follow the phase of the moon and those not regard seasons.

Solar hijri calendar: 21st of March is new year.

Hebrew calendar: 18th September will be the new year for 2020 in the Hebrew calendar.

5 0

3 years ago