In which of the following instrument is the image that is formed erect

Kevin is refinishing his rusty wheelbarrow. He moves his sandpaper back and forth 45 times over a rusty area, each time moving a

dmitriy555 [2]

W = _|....F*dx*cos(a)........With F=force, x=distance over which force acts on object,
.......0.............................and a=angle between force and direction of travel.

Since the force is constant in this case we don't need the equation to be an integral expression, and since the force in question - the force of friction - is always precisely opposite the direction of travel (which makes (a) equal to 180 deg, and cos(a) equal to -1) the equation can be rewritted like so:

W = F*x*(-1) ............ or ............. W = -F*x

The force of friction is given by the equation: Ffriction = Fnormal*(coeff of friction)

Also, note that the total work is the sum of all 45 passes by the sandpaper. So our final equation, when Ffriction is substituted, is:

W = (-45)(Fnormal)(coeff of friction)(distance)
W = (-45)...(1.8N).........(0.92).........(0.15m)
W = ................-11.178 Joules

5 0

3 years ago

If a racecar traveling at 6 m/s accelerates at 0.75 m/s over 30 seconds, what is its

Elina [12.6K]

Answer:

The importance of learning is that it helps the individual to acquire the necessary skills through learning and knowledge so that he can achieve his set goals. An important fact about learning is that it is a means to improve knowledge and gain skills that will help in reaching specific goals.

Explanation:

The importance of learning is that it helps the individual to acquire the necessary skills through learning and knowledge so that he can achieve his set goals. An important fact about learning is that it is a means to improve knowledge and gain skills that will help in reaching specific goals.

8 0

3 years ago

I need so much help 50 points!!!!!! complete the graph

motikmotik

First Symbol : Cobalt (Co)

Its Group Number - 9

Its Period Number - 4

Its Family Name - Transition Metal

Second Symbol : Silicon (Si)

Its Group Number - 14

Its Period Number - 2

Its Family Name - Semiconductor

Third Symbol : Astatine (At)

Its Group Number - 17

Its Period Number - 6

Its Family Name - Halogen

Fourth Symbol : Magnesium (Mg)

Its Group Number - 2

Its Period Number - 3

Its Family Name - Alkaline Earth Metal

Fifth Symbol : Xenon (Xe)

Its Group Number - 18

Its Period Number - 5

Its Family Name - Noble Gas

6 0

3 years ago

How many milliliters of water at 25.0°C with a density of 0.997 g/mL must be mixed with 162 mL of coffee at 94.6°C so that the r

Andre45 [30]

Answer:

The volume of water is 139 mL.

Explanation:

Due to the Law of conservation of energy, the heat lost by coffee is equal to the heat gained by the water, that is, the sum of heats is equal to zero.

$Q_{coffee} + Q_{water} = 0\\Q_{coffee} = - Q_{water}$

The heat (Q) can be calculated using the following expression:

$Q=c \times m \times \Delta T$

where,

c is the specific heat of each substance

m is the mass of each substance

ΔT is the difference in temperature for each substance

The mass of coffee is:

$162mL.\frac{0.997g}{mL} = 162g$

Then,

$Q_{coffee} = - Q_{water}\\c_{c} \times m_{c} \times \Delta T_{c} = -c_{w} \times m_{w} \times \Delta T_{w}\\m_{c} \times \Delta T_{c} = -m_{w} \times \Delta T_{w}\\m_{w} = \frac{m_{c} \times \Delta T_{c}}{-\Delta T_{w}} \\m_{w}=\frac{162g \times (62.5 \°C - 94.6 \°C ) }{-(62.5 \°C - 25.0 \°C)} \\m_{w} = 139 g$

The volume of water is:

$139g.\frac{1mL}{0.997g} =139mL$

7 0

4 years ago

calculate the efficiency of a light bulb that had an input of 400 j transfers 100j as a light and 300j as heat.

beks73 [17]

Efficiency = useful energy out / total energy in x 100
= 100/400 x 100
=0.25 x 100
= 25%

25%

6 0

3 years ago