Consider the chemical reaction involving graphite as the reactant:

6. Four people are trying to help push and lift a refrigerator up a series of stairs. Jim pushes

professor190 [17]

Answer:

Net force due to all on the refrigerator is 400 N

Explanation:

As we know that two people are pushing the refrigerator while other two people are lifting the refrigerator

So net push force on the refrigerator is given as

$F = F_1 + F_2$

$F = 60 + 210$

$F_1 = 270 N$

Similarly net lift force on the refrigerator is given as

$F = F_1' + F_2'$

$F = 200 + 95$

$F_2 = 295 N$

Now net force on the refrigerator is given as

$F_{net} =\sqrt{F_1^2 + F_2^2}$

$F_{net} = \sqrt{270^2 + 295^2}$

$F_{net} = 400 N$

4 0

4 years ago

At the start of a basketball game, a referee tosses a basketball straight into the air by giving it some initial speed. After be

max2010maxim [7]

Answer:

0.32 m.

Explanation:

To solve this problem, we must recognise that:

1. At the maximum height, the velocity of the ball is zero.

2. When the velocity of the ball is 2.5 m/s above the ground, it is assumed that the potential energy and kinetic energy of the ball are the same.

With the above information in mind, we shall determine the height of the ball when it has a speed of 2.5 m/s. This can be obtained as follow:

Mass (m) = constant

Acceleration due to gravity (g) = 9.8 m/s²

Velocity (v) = 2.5 m/s

Height (h) =?

PE = KE

Recall:

PE = mgh

KE = ½mv²

Thus,

PE = KE

mgh = ½mv²

Cancel m from both side

gh = ½v²

9.8 × h = ½ × 2.5²

9.8 × h = ½ × 6.25

9.8 × h = 3.125

Divide both side by 9.8

h = 3.125 / 9.8

h = 0.32 m

Thus, the height of the ball when it has a speed of 2.5 m/s is 0.32 m.

3 0

3 years ago

The reason Senators are in office for 6 years is...

Airida [17]

I think it’s answer 1 to separate senators fr om the whims or the general public

8 0

3 years ago

Two energy transfers take place when a book hits the ground, Which type of energy transfers are those

bazaltina [42]

Answer:

I think that when a book hits the ground its potential energy converts into kinetic energy and then kinetic energy is transformed into sound and heat energy.

Explanation:

6 0

3 years ago

4. Johnny exerts a 3.55 N rightward force on a 0.200-kg box to accelerate it across a low-friction track. If the total resistanc

muminat

a) $15.2 m/s^2$

b) 1.96 N

c) 1.96 N

Explanation:

a)

To find the acceleration of the box, we apply Newton's second law of motion:

$\sum F=ma$

where

$\sum F$ is the net force on the box

m is the mass of the box

a is its acceleration

Here we have to consider the horizontal direction, which is the one in which the box is moving. The net force is given by:

$\sum F=3.55 N - 0.52 N=3.03 N$

which is the difference between the forward force and the resistive force. Then we have

m = 0.200 kg (mass of the box)

Therefore, the acceleration of the box is:

$a=\frac{\sum F}{m}=\frac{3.03}{0.200}=15.2 m/s^2$

b)

The gravitational force (also called weight) is the force with which an object is pulled by the Earth towards the Earth's centre.

It is given by

$F_g = mg$

where

m is the mass of the object

g is the acceleration due to gravity

In this problem, we have:

m = 0.200 kg is the mass of the box

$g=9.8 m/s^2$ is the acceleration due to gravity

Therefore, the gravitational force on the box is:

$F_g=(0.200)(9.8)=1.96 N$

c)

The normal force is the force with which a surface pushes back on an object.

For an object lying on a flat surface, there are two forces acting along the vertical direction:

- The gravitational force, $F_g$ , which pushes the object downward

- The normal force, N, which pushes the object upward

As the object is at rest, the vertical acceleration of the object is zero, therefore according to Newton's second law of motion, the net force must be zero:

$\sum F=F_g-N=0$

Which means that the normal force is equal to the gravitational force:

$N=F_g$

And so, for the box in this problem, the normal force is

$N=1.96 N$

6 0

4 years ago