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2 years ago

A blue puck has a velocity of 3i –4j m/s. Its mass is 20 kg. What is its momentum?

Physics

2 answers:

damaskus [11]2 years ago

6 0

P = m * v
v = {3i - 4j} = square root (3^2 + 4^2) = 5
P = 20 * 5
P = 100 kg m/s

Tom [10]2 years ago

3 0

Magnitude:

√(3² + 4²) = √(9 + 16) = √25 = 5

Momentum = (mass) x (velocity) = (20kg x 5m/s) = 100 kg-m/s

Direction:

3i - 4j is in the direction tan⁻¹(-4/3) = 53.1 south of east.

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A girl is shown at position A on a swing when the seat is directly below the support bar. The seat is then at height A as shown

MrRa [10]

Answer:

1. The potential energy of the swing is the greatest at the position B.

2. As the swing moves from point B to point A, the kinetic energy is increasing.

Explanation:

Even though the syntax of the text is not completely clear, likely because it accompanies a drawing that is not included, it results clear that the posittion A is where the seat is at the lowest position, and the position B is upper.

The gravitational potential energy is directly proportional to the height of the objects with respect to some reference altitude. Thus, when the seat is at the position A the swing has the smallest potential energy and when the seat is at the position B the swing has the greatest potential energy.

Regarding the forms of energy, as the swing moves from point B to point A, it is going downward, gaining kinetic energy (speed) at the expense of the potential energy (losing altitude). When the seat passes by the position A, the kinetic energy is maximum and the potential energy is miminum. Then the seat starts to gain altitude again, losing the kinetic energy and gaining potential energy, up to it gets to the other end,

7 0

2 years ago

Read 2 more answers

As a rough approximation, the human body may be considered to be a cylinder of length L=2.0m and circumference C=0.8m. (To simpl

Brilliant_brown [7]

Answer:

Thermal Power = 460W

Explanation:

From Stephan-Boltzmann Law Formula;

P = єσT⁴A

Where,

P = Radiation energy

σ = Stefan-Boltzmann Constant

T = absolute temperature in Kelvin

є = Emissivity of the material.

A=Area of the emitting body

Now, σ = 5.67 x 10^(-8)

є = 0.6

Temperature = 30°C and coverting to kelvin = 30 + 273 = 303K

Area ; since we are to consider the sides of the human body as 2m and 0.8m,thus area = 2 x 0.8 = 1.6

Thus thermal power = 0.6 x 5.67 x 10^(-8) x303⁴ x 1.6 = 458. 8W

Normally, we approximate to the nearest 10W. Thus, thermal power is approximately 460W

4 0

2 years ago

Observe: Up until now, all the problems you have solved have involved converting only one unit. However, some conversion problem

ipn [44]

Answer:

t is appropriate to clarify that units such as time and angles the transformation is not in base ten, for example:

60 s = 1 min

60 min = 1 h

24 h = 1 day

Therefore, for this transformation, you must be more careful

the length transformation is base 10

Explanation:

In many exercises the units used are transformed by equations into other units called derivatives, in general the transformation of derived units is the product of the transformation of the constituent units.

In the example of velocity, the derivative unit is m / s, which is why it works in the same way that you transform length and time if in the equation it is multiplying it is multiplied and if it is dividing it is divided.

It is appropriate to clarify that units such as time and angles the transformation is not in base ten, for example:

60 s = 1 min

60 min = 1 h

24 h = 1 day

Therefore, for this transformation, you must be more careful

the length transformation is base 10

1000 m = 1 km

7 0

2 years ago

A measuring cylinder contains 60cm3 of oil at 0 celcius. When a piece of ice was roped into the cylinder it sank completely in o

mariarad [96]

Answer:

$S_i=\frac{9}{10} =0.9$

Explanation:

Given:

volume of oil in the cylinder, $V_o=60\ cm^2$

volume of the oil level when the ice is immersed, $V=90\ cm^3$

the volume level of oil when the ice melted, $V'=87\ cm^3$

Now, therefore the volume of ice:

$V_i=V-V_o$

$V_i=90-60$

$V_i=30\ cm^3$

Now the volume of water:

$V_w=V'-V_o$

$V_w=87-60$

$V_w=27\ cm^3$

As we know that the relative density is the ratio of density of the substance to the density of water.

So, the relative density of ice:

$S_i=\frac{\rho_i}{\rho_w}$ .....................(1)

as we know that density is given as:

$\rm \rho=\frac{mass}{volume}$

now eq. (1)

$S_i=\frac{m}{V_{i}}\div \frac{m}{V_w}$

where, m = mass of the water or the ice which remains constant in any phase

$S_i=\frac{V_w}{V_i}$

$S_i=\frac{27}{30}$

$S_i=\frac{9}{10} =0.9$

7 0

2 years ago

A passenger bus is travelling 28.0 m/s to the right when the driver applies the brakes. The bus stops in 5.00 s. What is the acc

MAVERICK [17]

Change in velocity = d(v)
d(v) = v2 - v1 where v1 = initial speed, v2 = final speed
v1 = 28.0 m/s to the right
v2 = 0.00 m/s
d(v) = (0 - 28)m/s = -28 m/s to the right

Change in time = d(t)
d(t) = t2 - t1 where t1 = initial elapsed time, t2 = final elapsed time
t1 = 0.00 s
t2 = 5.00 s
d(t) = (5.00 - 0.00)s = 5.00s

Average acceleration = d(v) / d(t)
(-28.0 m/s) / (5.00 s)
(-28.0 m)/s * 1 / (5.00 s) = -5.60 m/s² to the right

3 0

2 years ago

Read 2 more answers