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3 years ago

A mimibus drives with a constant speed of 39 km/h. how far can it travel in 1.94 hours?

Physics

1 answer:

Rufina [12.5K]3 years ago

4 0

Answer:

<em>The minibus traveled 75.66 km</em>

Explanation:

<u>Motion with Constant Speed </u>

An object is said to travel at constant speed if the ratio of the distance traveled by the time taken is constant.

The formula to calculate the speed is:

$\displaystyle v=\frac{d}{t}$

Where

v = Speed of the object

d = Distance traveled

t = Time taken to travel d.

From the equation above, we solve for d:

d = v . t

The minibus has a constant speed of v=39 km/h and it's required to find the distance it travels in t=1.94 hours.

Calculating the distance:

d = 39 km/h * 1.94 h

d = 75.66 km

The minibus traveled 75.66 km

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Recycled plastics cannot be used to produce new food containers because ___

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they cannot be sterilized

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4 years ago

The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have st

irina [24]

Complete Question:

The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have studied the change in length of the knee extensor tendon in sprinters and nonathletes. They find (on average) that the sprinters' tendons stretch 43 mm , while nonathletes' stretch only 32 mm . The spring constant for the tendon is the same for both groups, $31 {\rm {N}/{mm}}$ . What is the difference in maximum stored energy between the sprinters and the nonathlethes?

Answer:

$\triangle E = 12.79 J$

Explanation:

Sprinters' tendons stretch, $x_s = 43 mm = 0.043 m$

Non athletes' stretch, $x_n = 32 mm = 0.032 m$

Spring constant for the two groups, k = 31 N/mm = 3100 N/m

Maximum Energy stored in the sprinter, $E_s = 0.5kx_s^2$

Maximum energy stored in the non athletes, $E_m = 0.5kx_n^2$

Difference in maximum stored energy between the sprinters and the non-athlethes:

$\triangle E = E_s - E_n = 0.5k(x_s^2 - x_n^2)\\\triangle E = 0.5*3100* (0.043^2 - 0.032^2)\\\triangle E = 0.5*31000*0.000825\\\triangle E = 12.79 J$

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4 years ago

KE=0.5.m.v2 or PE=m.g.h

LUCKY_DIMON [66]

Answer:

1. 37.8J

2. 18 Billion Joules, 18 Gigajoules

3. 9.81 Billion Joules, 9.81 Gigajoules

Explanation:

Use the formulas provided,

KE=(1/2)mv^2 and PE=mgh, noting that g=9.81

7 0

3 years ago

Read 2 more answers

A 10 kg box is 1.3 m above the ground. How much potential energy does it have? (g on Earth of 9.8 m/s?

Volgvan

Potential energy = mgh
Potential energy = 10 x 9.8 x 1.3
Potential energy = 127.4 J

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3 years ago

a. Give an example of a galvanic cell. What kind of reaction occurs in a galvanic cell? b. If one electrode in a galvanic cell i

Burka [1]

Answer:

a) Batteries and fuel cells are examples of galvanic cell

b) Ag-cathode and Zn-anode

c) Cell notation: Zn(s)|Zn²⁺(aq) || Ag⁺(aq)|Ag(s)

Explanation:

a) A galvanic cell is an electrochemical cell in which chemical energy is converted to electrical energy. The chemical reaction which drives a galvanic cell is a redox reaction i.e. a reduction-oxidation process.

A typical galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs. Batteries and fuel cells are examples of galvanic cells.

b) The nature of the electrode that will serve as an anode or cathode depends on the value of the standard reduction potential (E⁰) of that electrode. The electrode with a higher or more positive the value of E⁰ serves as the cathode and the other will function as an anode.

In the given case, the E⁰ values from the standard reduction potential table are:

E⁰(Zn/Zn2+) = -0.763 V

E°(Ag/Ag+)=+0.799 V

Therefore, Ag will be the cathode and Zn will be the anode

c) In the standard cell notation, the anode half cell is written on the left followed by the salt bridge '||' and finally the cathode half cell to the right.

Zn(s)|Zn²⁺(aq) || Ag⁺(aq)|Ag(s)

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3 years ago