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1.)A tank travels at a rate of 10.0 km/hr for 12.00 minutes, then at 15.0 km/hr for 8.00

rosijanka [135]

12.00 min = 0.2 hr

8.00 min = 0.15 hr

Total distance:

(10.0 km/hr) (0.2 hr) + (15.0 km/hr) (0.15 hr) + (20.0 km/hr) (0.2 hr)

= 8.25 km

Average speed:

(10.0 km/hr + 15.0 km/hr + 20.0 km/hr) / 3

= 15 km/hr

Change in position:

(10.0 km/hr) (0.2 hr) + (15.0 km/hr) (0.15 hr) - (20.0 km/hr) (0.2 hr)

= 0.25 km

Average velocity:

(10.0 km/hr + 15.0 km/hr - 20.0 km/hr) / 3

≈ 1.67 m/s

8 0

3 years ago

Which energy transfer occurs when a cube of ice is placed in a glass of water?

Daniel [21]

Acetic acid is a weak acid and sodium hydroxide is strong base. Salts of the two will hydrolyse to give basic solution. So, at neutral point, pH of the solution will be greater than 8.

5 0

3 years ago

Which one of the following statements does not accurately describe vibrations?

Ivanshal [37]

This is an example of resonance - when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion. The result of resonance is always a large vibration.

Answer D. Forced vibrations, such as those between a tuning fork and a large cabinet surface, result in a much lower sound than was produced by the original vibrating body Because this statement contridicts the above statement, it is not accurate

6 0

3 years ago

Read 2 more answers

A horizontal compass is placed 21 cm due south from a straight vertical wire carrying a 36 a current downward. in what direction

Anit [1.1K]

The needle of a compass will always lies along the magnetic field lines of the earth.
A magnetic declination at a point on the earth’s surface equal to zero implies that
the horizontal component of the earth’s magnetic field line at that specific point lies along
the line of the north-south magnetic poles.

The presence of a current-carrying wire creates an additional 
magnetic field that combines with the earth’s magnetic field. Since magnetic
fields are vector quantities, therefore the magnetic field of the earth and the magnetic field of the vertical wire must be combined vectorially.

Where:

B1 = magnetic field of the earth along the x-axis = 0.45 × 10 ⁻ ⁴ T

B2 = magnetic field due to the straight vertical wire along the y-axis

We can calculate for B2 using Amperes Law:

B2 = μ₀ i / [ 2 π R ]

B2 = [ 4π × 10 ⁻ ⁷ T • m / A ] ( 36 A ) / [ 2 π (0.21 m ) ] 
B2 = 5.97 × 10 ⁻ ⁵ T = 0.60 × 10 ⁻ ⁴ T

The angle can be calculated using tan function:
tan θ = y / x = B₂ / B₁ = 0.60 × 10 ⁻ ⁴ T / 0.45 × 10 ⁻ ⁴ T 
tan θ = 1.326

θ = 53°

The compass needle points along the direction of 53° west of north.

8 0

3 years ago

A model rocket is shot directly upward, rises to its maximum height and then returns to its launch position in 10.0 s. Assuming

worty [1.4K]

d. 49.0 m/s

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3 0

3 years ago