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3 years ago

What is the reaction force if a girl pulls on a cow?

1 answer:

8 0

Answer : B) The cow pulls back on the girl.

From newton’s third law we know that every action has a reaction force pushing back. So when the girl pulls on a cow, the cow is pulling back on her.

You might be interested in

The weight of a basketball with a mass of 0.5 kg is _N.

Mariana [72]

Answer:

4.9N

Explanation:

The formula for weight is F = ma.

You plug in the mass of 0.5kg and an acceleration of 9.8 to get

F = (0.5)(9.8)

F = 4.9N

3 0

3 years ago

What law states that, in any process, energy is neither created nor destroyed?

kupik [55]

The law of conservation of energy.

8 0

2 years ago

The law of conservation of mass states that _______________________________.

xenn [34]

Energy cannot be created nor be destroyed

3 0

2 years ago

A certain freely falling object, released from rest, requires 1.50 s to travel the last 30.0 m before it hits the ground. From w

BaLLatris [955]

Answer:

The object fell from about 38.14 meters

Explanation:

We can use the formula for displacement under accelerated motion due to gravity to find the velocity of the object had 30 m before hitting the ground :

$y_f-y_i=v_i * \,t-\frac{9.8}{2} \,t^2\\0-30=v_i \,(1.5)-4.9\,(1.5)^2\\-18.975=v_i\,(1.5)\\v_i=-12.65\,\,\frac{m}{s}$

Now, knowing this velocity, we can find the time it took to fall from the initial position to 30 m before hitting the ground:

$v_f=v_i-g\,*\,t\\-12.65=0-g \,*\,t\\t=\frac{12.65}{g} \\t\approx1.29\,\,s$

And now we can find what is the total distance covered in 1.5 s plus 1.29 seconds for this free falling object:

$y_f-y_i=v_i * \,t-\frac{9.8}{2} \,t^2\\0-y_i=0-\frac{9.8}{2} \,(2.79)^2\\-y_i=-38.14\\y_i=38.14\,\,m$

7 0

2 years ago

John does 3.2J of work to lower the window shade in her bedroom a distance of 0.8m. How much force must John exert on the window

Gekata [30.6K]

Answer:

$\boxed {\boxed {\sf 4 \ Newtons}}}$

Explanation:

Work is energy transferred when an object is moved. It is the product of force and distance.

$W= F*d$

John did 3.2 Joules of work or 3.2 Newton meters of work (the units are equivalent). The window shade was lowered a distance of 0.8 meters.

W=3.2 N*m
d= 0.8 m

Substitute the values into the formula.

$3.2 \ N *m = F * 0.8 \ m$

We are solving for the force, so we must isolate the variable F. It is being multiplied by 0.8 meters. The inverse operation of multiplication is division, so divide both sides of the equation by 0.8 m.

$\frac {3.2 \ N*m}{0.8 \ m}= \frac{ F* 0.8 \ m}{0.8 \ m}$

The units of meters cancel.

$\frac {3.2 \ N}{0.8 }=F$

$4 \ N = F$

John must exert 4 Newtons of force.

4 0

2 years ago