All categories

3 years ago

Please help! i'm horrible at this

Physics

1 answer:

frez [133]3 years ago

4 0

Answer:

a = Δv/t = (vf - vi)/t = (0 - 5)/4 = -1.25 m/s²

Explanation:

You may or may not need the negative sign, depending on how the question designer was thinking about the problem.

You might be interested in

10. A hockey puck with mass 0.3 kg is sliding along ice that can be considered frictionless. The puck’s velocity is 20 m/s when

SVEN [57.7K]

Answer:

$d = \frac{v^2_i}{2a}= \frac{(20m/s)^2}{2* 3.43 m/s^2}=58.309m$

Explanation:

For this case we can use the second law of Newton given by:

$\sum F = ma$

The friction force on this case is defined as :

$F_f = \mu_k N = \mu_k mg$

Where N represent the normal force, $\mu_k$ the kinetic friction coeffient and a the acceleration.

For this case we can assume that the only force is the friction force and we have:

$F_f = ma$

Replacing the friction force we got:

$\mu_k mg = ma$

We can cancel the mass and we have:

$a = \mu_k g = 0.35 *9.8 \frac{m}{s^2}= 3.43 \frac{m}{s^2}$

And now we can use the following kinematic formula in order to find the distance travelled:

$v^2_f = v^2_i - 2ad$

Assuming the final velocity is 0 we can find the distance like this:

$d = \frac{v^2_i}{2a}= \frac{(20m/s)^2}{2* 3.43 m/s^2}=58.309m$

5 0

3 years ago

Write down short notes on:<br>c. Power

Fudgin [204]

Answer: In the International System of Units, the unit of power is the watt, equal to one joule per second. In older works, power is sometimes called activity. Power is a scalar quantity.

Explanation: SI unit: watt (W)

In SI base units: kg⋅m2⋅s−3

Derivations from other quantities: P = E/t; P = F...

4 0

3 years ago

A system consists of electrons and protons only. It contains 150 electrons and has a total charge of +22e. What is the mass of t

liubo4ka [24]

According to the statements the number of electrons is 150, then

e = 150

But there is a positive charge of +22e, then the number of protons would be

p = 150+172

If the mass of the electrons is

$m_e = 9.11*10^{-31} kg$

And the mass of the protong is

$m_p = 1.673*10^{-27}kg$

We have that the total mass of the system would be

$m = e*m_e +pm_p$

$m = 150 * (9.11*10^{-31})+170(1.673*10^{-27})$

$m = 2.84547*10^{-25} kg$

5 0

3 years ago

An airplane accelerates from rest to its required takeoff speed with an acceleration 5.0 m/s^2 after travelling on the runway a

Alex Ar [27]

Answer:

Explanation:

.75 km = 750 m

acceleration a = 5 m/s²

distance s = 750 m

initial velocity u = 0

Final velocity v = ?

v² = u² + 2as

v² = 0 + 2 x 5 x 750

v = 86.60 m /s.

5 0

3 years ago

Encuentre en km.h la velocidad de un tigre que corre 550 km.h en 69min

Len [333]

Answer:

v = 478.26 km/h

Explanation:

The question is "find in km.h the speed of a tiger that runs 550 km in 69min"

Distance, d = 550 km

Time, t = 69 min = 1.15 h

We need to find the speed of the tiger. The speed of an object is equal to the total distance covered divided by time taken. So,

$v=\dfrac{550\ km}{1.15\ h}\\\\v=478.26\ km/h$

So, the speed of the tiger is 478.26 km/h.

8 0

3 years ago