All categories

4 years ago

Ann is driving down a street at 61 km/h.

Physics

1 answer:

Wittaler [7]4 years ago

4 0

Answer:

12.267 seconds approximately.

Explanation:

The units can be simplified into m/s, in which case you would have 61000/3600. Simplify that to 16 and 17/18. This is your meters per second, so multiply that by .724 to get the answer.

You might be interested in

An orchestra is practicing a piece that is to be played at an allegro tempo. The conductor sets a metronome at 160 beats per min

MariettaO [177]

To develop this problem it is necessary to apply the concepts related to the Frequency according to the Period. Frequency is the number of repetitions per unit of time of any periodic event. The period is the length of time of each repetitive event, so the period is the reciprocal of the frequency.

The frequency of the metronome in seconds would then be

$f = 160 \frac{beats}{min} (\frac{1min}{60s})$

$f = 2.67\frac{beats}{s}$

Since the frequency is inversely proportional to the period then

$T = \frac{1}{f}$

$T = \frac{1}{2.67}$

$T = 0.375s = 375ms$

The correct answer is B. 375ms

4 0

3 years ago

1. A particle is projected vertically upwards with a velocity of 30 ms from a point 0. Find (a) the maximum height reached(b) th

Bogdan [553]

Assuming the particle is in free fall once it is shot up, its vertical velocity v at time t is

v = 30 m/s - g t

where g = 9.8 m/s² is the magnitude of the acceleration due to gravity, and its height y is given by

y = (30 m/s) t - 1/2 g t ²

(a) At its maximum height, the particle has 0 velocity, which occurs for

0 = 30 m/s - g t

t = (30 m/s) / g ≈ 3.06 s

at which point the particle's maximum height would be

y = (30 m/s) (3.06 s) - 1/2 g (3.06 s)² ≈ 45.9184 m ≈ 46 m

(b) It takes twice the time found in part (a) to return to 0 height, t ≈ 6.1 s.

(c) The particle falls 35 m below its starting point when

-35 m = (30 m/s) t - 1/2 g t ²

Solve for t to get a time of about t ≈ 7.1 s

7 0

3 years ago

Jan is holding an ice cube. What causes the ice to melt?

zmey [24]

It would be the temperature of her hand and also because it is going through the process of the water cycle it is changing from a solid to a liquid

6 0

3 years ago

On top of Mount Everest, the temperature is -19 ∘C in July. Being a physicist, you determine by how many degrees Celsius one nee

kondaur [170]

Answer:

254 °C

Explanation:

The average kinetic energy of gas molecules K = 3RT/2N where R = gas constant = 8.314 J/mol-K, N = avogadro's constant = 6.022 × 10²³ atoms/mol

T = temperature in Kelvin.

Let K be its average kinetic energy at t = -19°C = 273 + (-19) = 273 - 19 = 254 K = T. K = 3RT/2N = 3 × 8.314 J/mol-K × 254 K/(2 × 6.022 × 10²³ atoms/mol) = 5.26 × 10⁻²¹ J

When its average kinetic energy doubles, it becomes K₁ = 2K = 2 × 5.26 × 10⁻²¹ = 10.52 × 10⁻²¹ J at temperature T₂. So,

K₁ = 3RT₁/2N

T₁ = 2NK₁/3R

T₁ = 2 × 6.022 × 10²³ atoms/mol × 10.52 × 10⁻²¹ J/3 × 8.314 J/mol-K = 508 K

The temperature difference is thus ΔT = T₁ - T = 508 K - 254 K = 254 K.

Since temperature change in kelvin scale equals temperature change in Celsius scale ΔT = 254 °C

So, we need to change the temperature of the air by 254 °C to double its average kinetic energy.

3 0

3 years ago

Choose the items that help to fully describe voltage.

Zina [86]

Answer:

the easy way to describe this is to use a light as an example.

Explanation:

Voltage is pretty much the loop used to help use a lightbulb to emit light. Without voltage, we would be unable to use lightbulbs. This applies to much more than a lightbulb, but it's the easiest way to describe how voltage works.

8 0

2 years ago