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3 years ago

9

You throw a football straight up. Air resistance can be neglected. (a) When the football is 4.00 m above where it left your hand

, it is moving upward at 0.500 m/s. What was the speed of the football when it left your hand

1 answer:

Oksana_A [137]3 years ago

4 0

Answer:

The speed of the football when it lift your hand is 8.86 m/s.

Explanation:

Given that,

Final speed of the football, v = 0.5 m/s

Height above the ground, s = 4 m

We need to find the speed of the football when it left your hand. The ball will move under the action of gravity. Using third equation of motion as:

$v^2-u^2=2gs\\\\u^2=v^2-2gs\\\\u^2=(0.5)^2-2\times (-9.8)\times 4\\\\u=8.86\ m/s$

So, the speed of the football when it lift your hand is 8.86 m/s. Hence, this is the required solution.

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Mike is standing on the roof of a building looking at the roof of the neighboring building that is 15 meters away and 10 meters

amid [387]

Answer:

Part a)

$t = 1.65 s$

Part b)

$x = 40.4 m$

Since the distance of other building is 15 m so YES it can make it to other building

Part c)

$v = 27.3 m/s$

direction of velocity is given as

$[tex]\theta = 26.35 degree$

Explanation:

Part a)

acceleration due to gravity on this planet is 3/4 times the gravity on earth

So the acceleration due to gravity on this new planet is given as

$a = \frac{3}{4}(9.81)$

$a = 7.36 m/s^2$

now the vertical displacement covered by the canister is given as

$y = 10 m$

now by kinematics we have

$y = \frac{1}{2}gt^2$

$10 = \frac{1}{2}(7.36)t^2$

$t = 1.65 s$

Part b)

Horizontal speed of the canister is given as

$v_x = 24.5 m/s$

now the distance moved by it

$x = v_x t$

$x = 24.5 (1.65)$

$x = 40.4 m$

Since the distance of other building is 15 m so YES it can make it to other building

Part c)

Final velocity in X direction will remains the same

$v_x = 24.5 m/s$

final velocity in Y direction

$v_y = v_i + at$

$v_y = 0 + (7.36)(1.65)$

$v_y = 12.14 m/s$

now magnitude of velocity is given as

$v = \sqrt{v_x^2 + v_y^2}$

$v = \sqrt{24.5^2 + 12.14^2}$

$v = 27.3 m/s$

direction of velocity is given as

$\theta = tan^{-1}\frac{v_y}{v_x}$

$\theta = tan^{-1}\frac{12.14}{24.5}$

$[tex]\theta = 26.35 degree$

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30 km/h is _________m/s?<br> A.)8.3<br> B.)5.6<br> C.)13.9<br> D.)11.1

Juli2301 [7.4K]

Answer:

Correct Option :- A

Explanation:

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2 years ago

2 resistors of resistance 1000 ohm and 2000 ohm are joined in series with a 100V supply. A voltmeter of internal resistance 4000

Vadim26 [7]

<h2>The voltmeter reading will be 35.7 volt </h2>

Explanation:

The resistor 1000 ohm and 4000 ohm are connected in parallel .

Their combined resistance is supposed R₁

Thus $\frac{1}{R_1}$ = $\frac{1}{1000}$ + $\frac{1}{4000}$

or R₁ = 800 ohm

Therefore the total resistance in circuit is = 2000 + 800 = 2800 ohm

Because these are in series .

We can find current flowing through the circuit I = $\frac{V}{R}$ = $\frac{100}{2800}$ = $\frac{1}{28}$

here R is total resistance .

The potential difference across 1000 ohm = $\frac{1}{28}$ x 1000 = 35.7 volt

Thus voltmeter reading will be 35.7 volt

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In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the sys

nydimaria [60]

Answer : The final energy of the system if the initial energy was 2000 J is, 3500 J

Solution :

(1) The equation used is,

$\Delta U=q+w\\\\U_{final}-U_{initial}=q+w$

where,

$U_{final}$ = final internal energy

$U_{initial}$ = initial internal energy

q = heat energy

w = work done

(2) The known variables are, q, w and $U_{initial}$

initial internal energy = $U_{initial}$ = 2000 J

heat energy = q = 1000 J

work done = w = 500 J

(3) Now plug the numbers into the equation, we get

$U_{final}-(2000J)=(1000J)+(500J)$

(4) By solving the terms, we get

$U_{final}-(2000J)=(1000J)+(500J)$

$U_{final}-(2000J)=1500J$

$U_{final}=2000J+1500J$

$U_{final}=3500J$

(5) Therefore, the final energy of the system if the initial energy was 2000 J is, 3500 J

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A 9V battery produces a 1.5A current in a piece of wire. What is the resistance of the wire?

MAVERICK [17]

Explanation:

Using Ohm's Law and a bit of substitution, we can use voltage divided by current to solve for resistance. Doing that, we'll get 6 Ohm.

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