Which is the force that slows moving things down?

A red ball is thrown down with an initial speed of 1.6 m/s from a height of 25 meters above the ground. Then, 0.4 seconds after

Radda [10]

Answer:

1. v = 22.2 m/s

2. t = 2.25 seconds

3. h = 27.05 m

4. t = 1.16 seconds

Explanation:

The questions involve motion under the influence of gravity

1. Using the formula v² = u² + 2gh

where u = 1.6 m/s; g= 9.81 m/s²; h = 25 m; v = ?

v² = (1.6)² + 2 * 9.81 * 25

√v² = √493.06

v = 22.2 m/s

2. Using h = ut + 1/2 gt²

where h = 25 m; u = 0 (since velocity on reaching the ground is zero); g = 9.81 m/s²; t = ?

therefore, h = 1/2 gt²

making t subject of the formula, t = √ (2*h /g)

t = √ (2 * 25 / 9.81)

t = 2.25 seconds

3. Time of travel for the blue ball, t = 2 - 0.4 = 1.6s

using h = ut - gt²

u = 24 m/s; t = 1.6 s; g = 9.81 m/s²

note: since the ball is travelling against gravity, g is negative

h = 24 * 1.6 - 11/2 * 9.81 * 1.6²

h = 38.4 - 12.55 = 25.85 m

since height above the ground is 1.2 m,

total height h = 25.85 m + 1.2 m

h = 27.05 m

4. Let the time of travel of the red ball be t seconds.

So the time of travel of the blue ball = (t - 0.4) seconds.

Both the balls are at the same height :

25 - s = 1.2 + h where s & h are the displacements of the red & the blue ball respectively.

25 - (ut + 1/2 gt2) = 1.2 + (ut - 1/2 gt2)

25 - (1.6 t + 0.5 * 9.8 t²) = 1.2 + (24(t-0.4) - 0.5*9.8*(t-0.4)²)

solving the equation above for the time after which both the balls are at the same height.

25 - 1.6t - 4.9t² = 1.2 + 24t - 9.6 - 4.9t² + 3.92t - 0.784

collecting like terms

(25 - 1.2 + 9.6 + 0.784) = (24 + 3.92 + 1.6) * t

t = 34.184 / 33.44

t = 1.16 seconds

6 0

3 years ago

A 523.2-W space heater is designed for operation in Germany, where household electrical outlets supply 230 V (rms) service. What

photoshop1234 [79]

Answer:

power = 142.4 W

Explanation:

power of heater in Germany (P₁) = 523.2 W

power of heater in America (P₂) = ?

outlet voltage in Germany (V₁) = 230 V

outlet voltage in America (V₂) = 120 V

While in Germany, power = $\frac{V₁^{2}}{R}$

523.2 = $\frac{230^{2}}{R}$

R = 101.1

While in America, also power = $\frac{V₂^{2}}{R}$

using the value of R gotten above

power = $\frac{120^{2}}{101.1}$

power = 142.4 W

6 0

3 years ago

The velocity of a car increases from 10 km/h to 50 km/h in 5 seconds. What is its acceleration?

mr Goodwill [35]

Answer:

2.22m/s^2

Explanation:

3 0

3 years ago

A cylindrical capacitor has an inner conductor of radius 1.5 mm andan outer conductor of radius 3.4 mm.The two conductors are se

kenny6666 [7]

Answer:

Part(a): The capacitance per unit length of the capacitor is $\bf{1.56 \times 10^{-10}}~F~m^{-1}$ .

Part(b): The charge in the inner shell is $+ 1.6 \times 10^{-10}~C$ and the charge of the outer shell is $- 1.6 \times 10^{-10}~C$ .

Explanation:

Part(a):

The capacitance ( $C$ ) per unit length of a cylindrical capacitor is given by

$C = \dfrac{2 \pi \epsilon_{0}}{log(b/a)}$

where ' $\epsilon_{0}$ ' is the permittivity of free space, ' $b$ ' is the radius of the outer shell and ' $a$ ' is the radius of the inner shell.

Given, $b = 3.4~mm = 0.0034~m$ and $a = 1.5~mm = 0.0015~m$ . We know, $\epsilon_{0} = 8.854 \times 10^{-12}~F~m^{-1}$ . Substituting the values in the above equation,

$C = \dfrac{2 \pi \times 8.85 \times 10^{-12}~F~m^{-1}}{log(0.0034/0.0015)} = 1.56 \times 10^{-10}~F~m^{-1}$

Part(b):

As the voltage on the inner conductor is higher than that of the outer conductor, positive charge resides on the inner shell and negative charge resides on the outer shell.

The charge ' $Q$ ' of a capacitor of length ' $L$ ' having capacitance ' $C$ ' and potential difference ' $V$ ' is given by

$Q = C~V~L$

Given, $V = 350~mV = 350 \times 10^{-3}~V$ and $L = 3.0~m$ . Substituting these values in the above expression

$Q = 1.56 \times 10^{-10}~F~m^{-1} \times 350 \times 10^{-3}~V \times 3~m = 1.6 \times 10^{-10}~C$

The charge in the inner shell is $+ 1.6 \times 10^{-10}~C$ and the charge of the outer shell is $- 1.6 \times 10^{-10}~C$ .

7 0

3 years ago

Parts of the brain

Contact [7]

Cerebrum: is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement.

Cerebellum: is located under the cerebrum. Its function is to coordinate muscle movements, maintain posture, and balance.

Brainstem: acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.

8 0

3 years ago

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