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3 years ago

A motorcycle and its driver has a mass of 145 kg. Answer the following questions about it, using correct units.

Physics

2 answers:

I am Lyosha [343]3 years ago

7 0

Answer:

(A) 45312.5 J

(B) 5075 J

Explanation:

m = 145 kg

(a) v = 25 m/s

The energy possessed by the body by virtue of its motion is called kinetic energy. The formula for kinetic energy is given by

$K = \frac{1}{2}mv^{2}$

$K = \frac{1}{2}\times 145\times 25^{2}$

K = 45312.5 Joule

(b) h = 3.5 m

The energy possessed by the body by virtue of its position is called potential energy.

P = mgh

P = 145 x 10 x 3.5

P = 5075 Joule

The sum of the kinetic energy and potential energy is called mechanical energy.

M.E. = 1/2 mv^2 + mgh

M.E. = 0.5 x 145 x 28 x 28 + 145 x 10 x 4

M.E. = 56840 + 5800

M.E. = 62640 Joule

inysia [295]3 years ago

4 0

a) KE=0.5*mv^2==0.5*145*25^2=45312.5 J

b) PE=mgh=145*9.8*3.5=4973.5 J

c) ME=KE+PE=m(0.5v^2+gh)=62524 J

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Answer:

a) The final pressure is 1.68 atm.

b) The work done by the gas is 305.3 J.

Explanation:

a) The final pressure of an isothermal expansion is given by:

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$T_{i} = T_{f}$

$\frac{P_{i}V_{i}}{nR} = \frac{P_{f}V_{f}}{nR}$

Where:

$P_{i}$ : is the initial pressure = 5.79 atm

$P_{f}$ : is the final pressure =?

$V_{i}$ : is the initial volume = 420 cm³

$V_{f}$ : is the final volume = 1450 cm³

n: is the number of moles of the gas

R: is the gas constant

$P_{f} = \frac{P_{i}V_{i}}{V_{f}} = \frac{5.79 atm*420 cm^{3}}{1450 cm^{3}} = 1.68 atm$

Hence, the final pressure is 1.68 atm.

b) The work done by the isothermal expansion is:

$W = P_{i}V_{i}ln(\frac{V_{f}}{V_{i}}) = 5.79 atm*\frac{101325 Pa}{1 atm}*420 cm^{3}*\frac{1 m^{3}}{(100 cm)^{3}}ln(\frac{1450 cm^{3}}{420 cm^{3}}) = 305.3 J$

Therefore, the work done by the gas is 305.3 J.

I hope it helps you!

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3 years ago

A compound microscope is equipped with two objective lenses (10x and 45x) and has a 10x ocular lens. The highest magnification a

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Answer:

450X

Explanation:

When a specimen is been viewed, both

objective and ocular lenses works together so that the object is magnified.

From the question,objective lenses are;

1)10x

2)45x

ocular lens= 10x

Highest magnification

= 10X ocular × 45X objective

=450X

This implies that the image that was viewed will appear 450 times the actual size.

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3 years ago

A force of 185 n is needed to keep a small boat moving at 2.39 m/s. what is the power required to keep the boat moving at the st

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We know, P = F . ΔV

P = 185 * 2.39 = 442.15 watt

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3 years ago

You have a set of calipers that can measure thicknesses of a few inches with an uncertainty of ± 0.005 inches. You measure the t

Bond [772]

Answer:

a) x = (0.0114 ± 0.0001) in , b) the number of decks is 5

Explanation:

a) The thickness of the deck of cards (d) is measured and the thickness of a card (x) is calculated

x = d / 52

x = 0.590 / 52

x = 0.011346 in

Let's look for uncertainty

Δx = dx /dd Δd

Δx = 1/52 Δd

Δx = 1/52 0.005

Δx = 0.0001 in

The result of the calculation is

x = (0.0114 ± 0.0001) in

b) You want to reduce the error to Δx = 0.00002, the number of cards to be measured is

#_cards = n 52

The formula for thickness is

x = d / n 52

Uncertainty

Δx = 1 / n 52 Δd

n = 1/52 Δd / Δx

n = 1/52 0.005 / 0.00002

n = 4.8

Since the number of decks must be an integer the number of decks is 5

3 0

3 years ago

A spring gun consists of a spring inside a plastic tube with spring constant, k. The spring can be compressed 20 cm from its equ

emmainna [20.7K]

Answer: The spring constant is K=392.4N/m

Explanation:

According to hook's law the applied force F will be directly proportional to the extension e produced provided the spring is not distorted

The force F=ke

Where k=spring constant

e= Extention produced

h=2m

Given that

e=20cm to meter 20/100= 0.2m

m=100g to kg m=100/1000= 0.1kg

But F=mg

Ignoring air resistance

assuming g=9.81m/s²

Since the compression causes the plastic ball to poses potential energy hence energy stored in the spring

E=1/2ke²=mgh

Substituting our values to find k

First we make k subject of formula

k=2mgh/e²

k=2*0.1*9.81*2/0.1²

K=3.921/0.01

K=392.4N/m

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3 years ago