All categories

2 years ago

What are similarities and differences of the 1st, 2nd, and 3rd class levers?

1 answer:

7 0

Similarities:
-- All three classes have a fulcrum (pivot).
-- All three classes have a point where the effort force is applied.
-- All three classes have a point where the load or resistance force is applied.
-- If you can find a place to stand and a lever that's long enough,
then you can move the Earth with a 1st or 2nd Class lever.

Differences:
-- The mechanical advantage of a 1st Class lever
can be greater than 1, equal to 1, or less than 1.
-- The mechanical advantage of a 2nd Class lever is always more than 1 .
-- The mechanical advantage of a 3rd Class lever is always less than 1 .

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A ball is thrown horizontally from a high cliff with a velocity of 5 m/s. Ignoring the slowing of the ball due to air resistance

Aleksandr-060686 [28]

If there's no air resistance, then there are no horizontal forces on the ball.
With no horizontal force, there's no horizontal acceleration, so the horizontal speed never changes. From the time it's tossed until it hits the ground, its horizontal speed is the same 5 m/s. (B)

7 0

3 years ago

Read 2 more answers

Please help me on these questions in the picture.

inessss [21]

2. Because it has gravity and gravity pulls it to the earth.
3. Because of the chemicals it has in it.
4. a. by running with it
    b. by pulling it.
    c. by turning it.
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3 0

2 years ago

Read 2 more answers

A hydraulic car jack needs to be designed so it can lift a 2903.57 lb car assuming that a person can exert a force of 24.41 lbs.

marishachu [46]

Answer:

Diameter of the piston would be 0.71 m (71.1 cm)

Explanation:

From the principle of pressure;

$\frac{F_{1} }{A_{1} }$ = $\frac{F_{2} }{A_{2} }$

Let $F_{1}$ = 2903.57 lb, $F_{2}$ = 24.41 lbs, $r_{2}$ = 3.26 cm = 0.0326 m.

$A_{2}$ = $\pi r^{2}$

= $\frac{22}{7}$ x $(0.0326)^{2}$

= 0.00334 $m^{2}$

So that:

$\frac{2903.57}{A_{1} }$ = $\frac{24.41}{0.00334}$

$A_{1}$ = $\frac{2903.57*0.00334}{24.41}$

= 0.3973

$A_{1}$ = 0.4 $m^{2}$

The radius of the piston can be determined by:

$A_{1}$ = $\pi r^{2}$

0.3973 = $\frac{22}{7}$ x $r^{2}$

$r^{2}$ = $\frac{0.3973*7}{22}$

= 0.1264

r = $\sqrt{0.1264}$

= 0.3555

r = 0.36 m

Diameter of the piston = 2 x r

= 2 x 0.3555

= 0.711

Diameter of the piston would be 0.71 m (71.1 cm).

4 0

2 years ago

A tennis ball with a speed of 25.9 m/s is moving perpendicular to a wall. After striking the wall,

mihalych1998 [28]

Answer:

$-3550.1 m/s^2$

Explanation:

The initial velocity of the ball is

u = +25.9 m/s (towards the wall)

while the final velocity of the ball is

v = -21.3157 m/s (away from the wall)

The time taken for the change in velocity to occur is

t = 0.0133 s

The acceleration can be calculated as the change in velocity divided by the time taken:

$a=\frac{v-u}{t}$

Substituting the numbers, we find:

$a=\frac{-21.3157-25.9}{0.0133}=-3550.1 m/s^2$

6 0

2 years ago

You have gas in a container with a movable piston. The walls of the container are thin enough so that its temperature stays the

bearhunter [10]

Answer:

New pressure of the gas increases by 26.5% with respect to initial pressure, new volume decreases 27% with respect to initial volume and new temperature decreases 8% with respect to initial volume.

Explanation:

If we assume the gas is a perfect gas we can use the perfect gas equation:

$PV=nRT$

For Isothermal process:

$\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{2}}{T_{2}}$ (1)

Where subscripts 1 shows before the isothermal process and 2 after it, because isothermal means constant temperature T1=T2, and pressure increases by 10% means P2=1,1*P1, using these facts on (1) we have:

$V_{2}=\frac{V_{1}}{1.1}$ (2)

For Isobaric process:

$\frac{P_{2}V_{2}}{T_{2}}=\frac{P_{3}V_{3}}{T_{3}}$ (3)

Where subscripts 2 shows before the isobaric process and 3 after it, because isobaric means constant pressure P2=P3, and volume decreases by 20% means V3=0.8*V2, using these facts on (3) we have:

$T_{3}=0.8T_{2}$ (4)

For Isochoric process:

$\frac{P_{3}V_{3}}{T_{3}}=\frac{P_{4}V_{4}}{T_{4}}$ (5)

Where subscripts 3 shows before the isochoric process and 4 after it, because isochoric means constant volume V3=V4, and temperature increases by 15% means T4=1.15*T3, using these facts on (5) we have:

$P_{4}=1.15P_{3}$ (6)