What is the speed of a bobsled whose distance-time graph indicates that it traveled 117m in 25s

Force F=2.0N i - 3.0N k acts on a pebble with position vectorr=0.50m j - 2.0m k relative to the origin. In unit vector notation,

klasskru [66]

Answer with Explanation:

We are given that

Force acts on a pebble= $2\hat{i}-3\hat{k}$ N

Position vector= $r=0.5\hat{j}-2\hat{k}$ m

a.We have to find the resulting torque on the pebble about origin.

Torque= $r\times F$

Substitute the values then we get

$Torque= (0.5j-2k)\times (2i-3k)$

Torque= $-k-1.5i-4j$ N-m

By using $i\times j=k,j\times k=i,k\times i=j,j\times i=-k,k\times j=-i,i\times k=-j,i\times i=j\times j=k\times k=0$

b. $r=2i-3k$

$r-r_1=(0.5j-2k)-(2i-3k)=-2i+0.5j+k$

Torque about point (2,0,-3)

$\tau=(-2i+0.5j+k)\times (2i-3k)$

$\tau=-6j-k-1.5i+2j=-1.5i-4j-k$ N-m

6 0

2 years ago

Wolves are a keystone species because they are _____. at the top of the food chain are physically the largest animal in the food

enot [183]

Answer:

Wolves are a keystone species because they are so important to the ecosystem that their removal causes a catastrophic disequilibrium.

Explanation:

Wolves are the predators available in the environment but they exist in relatively less number while comparing it with another species of animals. Wolves influence their pray which are influenced by plants. Thus, They are so important to the ecosystem that their removal causes a catastrophic disequilibrium.

4 0

2 years ago

Read 2 more answers

group of students is making model cars that will be propelled by model rocket engines. These engines provide a nearly constant t

iris [78.8K]

Answer:

increase.

Explanation:

According to the newton’s second law of motion force is expressed as product of mass and acceleration.

F = m a

If the force acting is constant, then.

m∝ $\frac{1}{a}$

That is if the mass of object increases the acceleration decreases and vice versa. The above equation is used when the force acting on the body is constant.

As the thrust force from the rocket engine is constant throughout there will be a variation in the mass or acceleration.

Thus, it won't stay the same.

As the weight of the car is maximum at the start because of the fuel present in the rocket engine and minimum at the end as the fuel burns throughout the journey of the car. Weight will be minimum at the end and hence acceleration is maximum at the end.

Thus, it won't decrease.

As the acceleration is going from minimum at the start to maximum at the end, therefore it is continuously increases throughout its journey.

Thus, it will increase.

7 0

2 years ago

The zone of earthquakes and volcanoes surrounding the pacific ocean is called

gulaghasi [49]

Answer:

The Ring of Fire

Explanation:

The ring of fire is also called the Circum-Pacific Belt, it is a path along the pacific ocean consisting of active volcanoes and frequent earthquakes.

It has a length of approximately 40,000 kilometers. It lies on the edge of tectonic plates where the in-earth vibrations and geothermal energies are prone to erupt out.

Ring of fire inhibits about 75% o the earth's volcanoes and 95% of earthquakes occur in this region.

3 0

2 years ago

If you were trying to describe the difference between power and work you could say...?

Paha777 [63]

Answer:

Look to the explanation

Explanation:

Work done is is the energy transferred to or from an object by means

of a force acting on the object.

Work is positive if energy transferred to the object, and work is

negative if energy transferred from the object.

Work = Force in the direction motion of object × its displacement

$W=F*s$

The SI unit of the work is joule (J)

Power is the rate of work

Power = work done ÷ time taken

Power = $\frac{F*s}{t}$

Displacement (s) ÷ time (t) = velocity (v)

Power = Force × velocity

$P=F*v$

The SI unit of the power is watt (w)

6 0

2 years ago