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3 years ago

8

What is the speed acquired by a freely falling object 4 seconds after being dropped from a rest position? Use units of meter per

second (m/s) and assume acceleration from gravity is 10 m/s2.

1 answer:

gizmo_the_mogwai [7]3 years ago

6 0

speed = 40 m/s

Explanation:

Since the object is dropped, V0y = 0.

Vy = V0y - gt

= -(10 m/s^2)(4 s)

= -40 m/s

This means that its velocity is 40 m/s downwards. Its speed is simply 40 m/s.

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An aluminum calorimeter with a mass of 100 g contains 250 g of water. The calorimeter and water are in thermal equilibrium at 10

Nadya [2.5K]

Answer:

1822.14 J/kg C

Explanation:

Mass of aluminum = 0.100 kg

Mass of Water = 0.250 kg

Mass of copper = 0.300 kg

Mass of unknown object = 0.70 kg

Initial temperature of Aluminum = 10 C

Initial temperature of water = 10 C

Initial temperature of copper = 30 C

Initial temperature of = 100 C

Final temperature of all substances = 20 C

Change in temperature of each of them Aluminum, water , copper and unknown material respectively = 10 C , 10 C , -10 C, -80 C respectively

Specific heat of each of them Aluminum, water , copper and unknown material respectively = 900,4186,387 and c respectively.

Heat gained by aluminum and water = (0.1)(900)(10) + (0.250)(4186)(10) = 11365 j

heat lost by copper and unknown material =(0.3)(387)(-10) = -1161

heat lost by unknown material = (0.070)(c)(-80) = -5.6 c

Now solve for c using the calorimetry principle.

Heat lost + Heat gained = 0

⇒ -5.6 c = -11365 - (-1161) = -10204 j

Specific heat of unknown material = - 10204 / -5.6

= 1822.14 j/kg C

b) Material having a specific heat of 1800 j /kg C is

Polyurethane elastomer.

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3 years ago

9. Calculate the distance (in km) that Charlie runs if he maintains the average

Karo-lina-s [1.5K]

<u>Correct Question:</u>

Calculate the distance (in km) charlie runs if he maintains an average speed of 8 km/hr for 1 hour

<u>Answer:</u>

The total distance covered by Charlie is 8 km in 1 hour.

<u>Explanation:</u>

The average velocity as given in the question is,

v = 8 km/hr

Total time taken,

$$t=1 hour$

As we know the formula to evaluate the total distance d when the average velocity and time is given;

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

$d=v \times t$

$d=8 \times 1$

$d=8 k m$

Hence, the total distance covered by Charlie in 1 hour will be 8 km.

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3 years ago

What is the theory behind a ticker tape lab?

Lana71 [14]

Purpose: experiments will use it to measure the straight-line accelerated motion of a human hand. The displacement data will be measured and velocity and acceleration will be calculated, run the ticker tape under the guides on the timer and under the carbon circle.Hope this helps! ; )

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3 years ago

The tip of the second hand of a clock moves in a circle of 20 cm circumference. In one minute the hand makes a complete revoluti

Cerrena [4.2K]

Answer:

$v_{avg} = 0$

Explanation:

As we know that average velocity is defined as the ratio of total displacement of the object and its time interval.

so here we can say

$v_{avg} = \frac{displacement}{time}$

now we know that in one complete revolution the total displacement of the tip of the seconds hand is zero

because it will have same position after one complete revolution from where it starts

so here we can say that the average velocity will be zero

$v_{avg} = 0$

7 0

3 years ago

A copper sphere was moving at 40 m/s when it hit another object. This caused all of the KE to be converted into thermal energy f

USPshnik [31]

Answer:

Temperature increase = 2.1 [C]

Explanation:

We need to identify the initial data of the problem.

v = velocity of the copper sphere = 40 [m/s]

Cp = heat capacity = 387 [J/kg*C]

The most important data given is the fact that when the shock occurs kinetic energy is transformed into thermal energy, therefore it will have to be:

$E_{k}=Q\\ E_{k}= kinetic energy [J]\\Q=thermal energy [J]\\Re-employment values and equalizing equations\\\\\frac{1}{2} *m*v^{2}=m*C_{p}*dT \\The masses are canceled \\\\dT=\frac{v^{2}}{C_{p} *2} \\dT=2.1 [C]$

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3 years ago