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2 years ago

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A GPS tracking device is placed in a police dog to monitor its whereabouts relative to the police station. At time t1 = 23 min,

the dog's displacement from the station is 1.2 km, 33° north of east. At time t2 = 57 min, the dog's displacement from the station is 2.0 km, 75° north of east. Find the magnitude and direction of the dog's average velocity between these two times.

1 answer:

Helga [31]2 years ago

8 0

Answer:

Explanation:

Let east be towards X-axis ant north be Y-axis. Let initial position of Dog be at

A . O be the police station (centre). Vector OA can be written as follows

OA = 1.2 Cos 33 + 1.2 Sin 33

O B =2 Cos 75 + 2 Sin 75.

Displacement A → B = OB - OA =2Cos75i +2 Sin 75j -1.2 Cos 33i -1.2 Sin 33j

= 2 x .2588 i+ 2x .966j - 1.2 x .8387i - 1.2 x .5446j = .5176i + 1.932 j- 1.0064i - .65356j

= -.4888 i + 1.27844j

Magnitude of displacement =√( .4888)² + ( 1.27844)²

= 1.405 km

Average velocity =1.405 / 57-23 km / min = 1.405 /34 x 60 =2.48 km/h

angle with x-axis ( east towards north ) ∅

Tan∅ =- 1.27844/.4888 = - 2.615

∅ = -69° or 111° towards north from east or 21° towards west from north.

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On a snowy day, max (mass = 15 kg) pulls his little sister maya in a sled (combined mass = 20 kg) through the slippery snow. max

sesenic [268]

Work done by a given force is given by

$W = F.d$

here on sled two forces will do work

1. Applied force by Max

2. Frictional force due to ground

Now by force diagram of sled we can see the angle of force and displacement

work done by Max = $W_1 = Fdcos\theta$

$W_1 = 12*5cos15$

$W_1 = 57.96 J$

Now similarly work done by frictional force

$W_2 = Fdcos\theta$

$W_2 = 4*5cos180$

$W_2= -20 J$

Now total work done on sled

$W_{net}= W_1 + W2$

$W_{net} = 57.96 - 20 = 37.96 J$

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2 years ago

The flat-bed trailer carries two 1500-kg beams with the upper beam secured by a cable. The coefficients of static friction betwe

Novosadov [1.4K]

Answer:

a) a= 8.33 m/s², T = 12.495 N , b) a = 2.45 m / s²

Explanation:

a) this is an exercise of Newton's second law. As the upper load is secured by a cable, it cannot be moved, so the lower load is determined by the maximum acceleration.

We apply Newton's second law to the lower charge

fr₁ + fr₂ = ma

The equation for the force of friction is

fr = μ N

Y Axis

N - W₁ –W₂ = 0

N = W₁ + W₂

N = (m₁ + m₂) g

Since the beams are the same, it has the same mass

N = 2 m g

We replace

μ₁ 2mg + μ₂ mg = m a

a = (2μ₁ + μ₂) g

a = (2 0.30 + 0.25) 9.8

a= 8.33 m/s²

Let's look for cable tension with beam 2

T = m₂ a

T = 1500 8.33

T = 12.495 N

b) For maximum deceleration the cable loses tension (T = 0 N), so as this beam has less friction is the one that will move first, we are assuming that the rope is horizontal

fr = m₂ a₂

N- w₂ = 0

N = W₂ = mg

μ₂ mg = m a₂

a = μ₂ g

a = 0.25 9.8

a = 2.45 m / s²

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2 years ago

Fill in the blanks to complete each statement about weathering. Weathering is the breakdown of rocks into smaller particles call

nevsk [136]

Answer:

sediments

Explanation:

Weathering is the breakdown of rocks into smaller particles called:

sediments

Weathering is the physical disintegration and chemical decay of rocks into smaller fragments to produce sediments. The product of rock weathering is basically sediments. Some of the sediments can be transformed to form soils when they combine with organic matter, water and air.

Physical weathering is when rocks are physically broken into smaller pieces, but the minerals in the rock remain the same.

Physical weathering

Physical weathering is the disintegration of rocks into smaller bits without altering the chemical make up of the minerals. The goal of physical weathering is to expose rock surface to action of chemical weathering.

When a rock is broken down in a way that changes the mineral composition, it is called chemical weathering

chemical weathering

Chemical weathering is the decay of rocks by altering the minerals in a rock.

Hope this Helps! c:

8 1

2 years ago

Read 3 more answers

The dial of a scale looks like this: 00.0kg. A physicist placed a spring on it. The dial read 00.6kg. He then placed a metal cha

saveliy_v [14]

Answer:

d. The scale's resolution is too low to read the change in mass

Explanation:

If we want to find the change in energy of the spring, we will have to use the Hooke's Law. Hooke's Law states that:

F = kx

since,

w = Fd

dw = Fdx

integrating and using value of F, we get:

ΔE = (0.5)kx²

where,

ΔE = Energy added to spring

k = spring constant

x = displacement

The spring constant is typically in range of 4900 to 29400 N/m.

So if we take the extreme case of 29400 N/m and lets say we assume an unusually, extreme case of 1 m compression, we get the value of energy added to be:

ΔE = (0.5)(29400 N/m)(1 m)²

ΔE = 1.47 x 10⁴ J

Now, if we convert this energy to mass from Einstein's equation, we get:

ΔE = Δmc²

Δm = ΔE/c²

Δm = (1.47 x 10⁴ J)/(3 x 10⁸ m/s)²

<u>Δm = 4.9 x 10⁻¹³ kg</u>

As, you can see from the answer that even for the most extreme cases the value of mass associated with the additional energy is of very low magnitude.

Since, the scale only gives the mass value upto 1 decimal place.

Thus, it can not determine such a small change. So, the correct option is:

<u>d. The scale's resolution is too low to read the change in mass</u>

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2 years ago

Before the student releases the cart by cutting the tinsel string, what forces are acting on the cart?

Naya [18.7K]

Answer: TENSION and WEIGHT

Explanation:

Force experienced by the spring is called TENSION while the WEIGHT is the gravitational pull on the body towards the earth surface. Therefore the forces acting on the cart are TENSION and WEIGHT(weight acts downwards (along negative y-axis) while the TENSION upward(along positive y-axis).

5 0

2 years ago