All categories

3 years ago

3) A dock worker pushes a 72 kg crate up a 2.0 m high,

Physics

1 answer:

Vlad [161]3 years ago

7 0

Work done on the crate is 1411.2 J

Explanation:

Work done is defined as the product of force and the distance moved by the object. The unit of work done is in joules and denoted by the symbol J.

Work done = F * d

where F represents the force and d represents the distance moved by the object.

mass = 72 kg , distance moved by the object is given by 2.0 m

Force F = mass * gravity = 72 * 9.8

= 705.6 N =706 N.

Work done = 706 * 2.0 = 1412 J.

You might be interested in

Atom X contains seven protons and seven neutrons. atom Z contains seven protons and eight neutrons. which of the following state

stiks02 [169]

Answer:

The correct answer is option A: they are isotopes.

Explanation:

From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.

Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.

The mass number is given by:

$A = p + n$

Where n is the number of neutrons and p is the number of protons.

For atom X and atom Z we have:

$A_{x} = 7 + 7 = 14$

$A_{z} = 7 + 8 = 15$

Hence, they have a different mass number.

We know that the element with 7 protons is nitrogen. The first isotope is $^{14}_{7}N$ and the second isotope is $^{15}_{7}N$ . Both isotopes are stables (they are not radioactive).

Therefore, the correct answer is option A: they are isotopes.

I hope it helps you!

3 0

3 years ago

Reading the temperature of a solution by using a thermometer is an example of a(n) ________.

blsea [12.9K]

Answer:

B. Observation

Explanation:

Using a thermometer to read the temperature of a solution is tantamount to the making an observation.

Observation are recorded using our senses of sight, taste, earing, feeling etc or by the use of instrument.

Through observation, data is usually collected to make inferences about an experiment.
An observation leads to the formulation of a hypothesis which is scientific guess that leads to experimental designs.
Conclusions are drawn from the information of data obtained from an experiment.

4 0

2 years ago

Which of the following describes pressure in a fluid?

PtichkaEL [24]

D. Pressure increases with increasing depth.

This occurs because there is more weight above you to increase the pressure.

7 0

3 years ago

Read 2 more answers

From a window that is 20 m from the ground a stone with a speed of 10m / s is thrown vertically upwards. Calculate:

Oduvanchick [21]

consider the motion in upward direction as positive and down direction as negative

Y₀ = initial position of the stone = 20 m

v₀ = initial velocity of the stone = 10 m/s

a = acceleration = - 9.8 m/s²

Y = final position of the stone when it reach the maximum height

v = final velocity at the maximum height = 0 m/s

t = time taken to reach the maximum height

Using the equation

v² = v₀² + 2 a (Y - Y₀)

0² = 10² + 2 (- 9.8) (Y - 20)

Y = 25.1 m

also using the equation

v = v₀ + a t

inserting the values

0 = 10 + (- 9.8) t

t = 1.02 sec

consider the motion in upward direction as positive and down direction as negative

Y₀ = initial position of the stone = 20 m

v₀ = initial velocity of the stone = 10 m/s

a = acceleration = - 9.8 m/s²

Y = final position of the stone when it reach the ground = 0 m

t = time taken to reach the ground

Using the equation

Y = Y₀ + v₀ t + (0.5) a t²

0 = 20 + 10 t + (0.5) (- 9.8) t²

t = 3.3 sec

3 0

3 years ago

Can the volume of a gas be measured?

Scilla [17]

Answer:

C. Just measure the volume of the container it is in

Explanation:

Another why of measuring the volume of gas is by filling a contractor with water then in invert a glass jar air will miss place the space taken by water then measure the volume of water misplaced to get the volume to air

5 0

3 years ago