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3 years ago

I throw a ball off the edge of a 15.0m cliff. If I threw it horizontally at 8.0 m/s, how much time did it take to fall?

1 answer:

3 0

Just ignore the horizontal component

if you have a vertical displacement of 15m, 0ms^1 initial velocity, end velocity is ignored, we know the acceleration due to gravity as 9.81ms^2 so we can work out the time using SUVAT

S=15
U=0
V=?
A=9.81
T=?

S=UT + 0.5 AT^2

UT=0

therefore,

S=0.5AT^2

rearrange to:

T=SQR (2S/A)

T = 1.75 seconds

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For the electric circuit given below, calculate: 3 (i) the equivalent resistance of the circuit, (ii) the total current drawn fr

Daniel [21]

Answer:

1)31/3Ω

2)18/31A

3)4.06V

Explanation:

According to the diagram and 10 Ω resistors are parallel to each other, parallel resistor can be calculated using the formula below

1/R= 1/R1 + 1/R2

But we know R1= 5 Ω and R2= 10 Ω

1/R= 1/5 + 1/10

R= 10/3 Ω

=3.33 Ω

Then if we follow the given figure, 10/3 Ω and 7Ω are now in series then

Req = 10/3 +7

Req= 31/3 Ω

Therefore, equivalent resistance = 31/3 Ω

According to ohms law we know that V= IR

Then I= V/R

Where I= current

R= resistance

V= voltage

I= 6/(31/3)

I= 18/31A

We can now calculate the voltage accross the resistor which is

V=(18/31)× 7

V=4.06V

Therefore, the voltage accross the 7 ohm resistor is 4.06V

CHECK THE FIQURE AT THE ATTACHMENT

3 0

3 years ago

A ball of mass is released from rest at a height of 30 how fast is it going when it hits the ground

elena55 [62]

Answer:

If the height is in metres, the speed is 24.25m/s

7 0

3 years ago

Which number is not found on the periodic table

miv72 [106K]

The letter “j” is never found on the periodic table. As for numbers, there’s an infinite amount

4 0

3 years ago

Teresa saw a large star outside of her window at ten o'clock last night.

nordsb [41]

Answer: The answer is C, Yes, her star will have appeared to move very slightly to the west.

Explanation: If your looking at a certain star, it usually goes to the west at night time very slightly, it doesn't go to the east because the Earth's axis tilts mostly on the west side. So it makes it true.

5 0

4 years ago

In a charming 19th-century hotel, an old-style elevator is connected to a counterweight by a cable that passes over a rotating d

melisa1 [442]

Answer:

2.38732 rpm

1.22625 rad/s²

163.292°

Explanation:

g = Acceleration due to gravity = 9.81 m/s²

a = Acceleration = $\frac{1}{8}g$

d = Diameter of wheel = 2 m

r = Radius of wheel = $\frac{d}{2}=\frac{2}{2}=1\ m$

v = Speed of elevator = 25 cm/s

Angular speed is given by

$\omega=\frac{v}{r}\\\Rightarrow \omega=\frac{0.25}{1}\\\Rightarrow \omega=0.25\ rad/s=0.25\times \frac{60}{2\pi}\\\Rightarrow \omega=2.38732\ rpm$

The angular speed of the wheel is 2.38732 rpm

Angular acceleration is given by

$\alpha=\frac{a}{r}\\\Rightarrow \alpha=\frac{\frac{1}{8}g}{r}\\\Rightarrow \alpha=\frac{\frac{1}{8}\times 9.81}{1}\\\Rightarrow \alpha=1.22625\ rad/s^2$

The angular acceleration of the wheel is 1.22625 rad/s²

Angular displacement is given by

$\theta=\frac{s}{r}\\\Rightarrow \theta=\frac{2.85}{1}\\\Rightarrow \theta=2.85\ rad=2.85\times \frac{360}{2\pi}\\ =163.292\ ^{\circ}$

The angle the disk turned when it has raised the elevator is 163.292°

4 0

3 years ago