All categories

2 years ago

Please help with 4 and 5, thank you :)

Physics

1 answer:

allochka39001 [22]2 years ago

6 0

Answer: #4

Sally is faster.

Explanation:

If you multiply Sallies it is going to be less than Jessica's.

You might be interested in

7. A roller coaster’s velocity at the top of a hill is 10 m/s. Two seconds later it reaches the bottom ofthe hill with a velocit

zheka24 [161]

Answer:

7) $a=8m/s^2$

8) $a=-5m/s^2$

9) $a=-1.5m/s^2$

10) $v=29.4m/s$

Explanation:

For the problems 7, 8 and 9 we just apply the definition of acceleration, since no more information is given, which is:

$a=\frac{\Delta v}{\Delta t}=\frac{v_f-v_i}{t_f-t_i}$

So for each problem we will have:

7) $a=\frac{26m/s-10m/s}{2s}=8m/s^2$

8) $a=\frac{10m/s-25m/s}{3s}=-5m/s^2$

9) $a=\frac{0m/s-15m/s}{10s}=-1.5m/s^2$

For the problem 10, we use the equation of velocity in accelerated motion:

$v=v_0+at$

Since the ball starts from rest and the acceleration is that of gravity (we take the downward direction positive), we have:

$v=(0m/s)+(9.8m/s)(3s)=29.4m/s$

5 0

2 years ago

Middle C, also known as do on the fixed do-solfge scale, is a note used when playing or singing music. The frequency of middle C

Ahat [919]

Answer:

The speed of sound for middle C is 345.01 m/s.

Explanation:

Given that,

The frequency of middle C is 261.63 Hz

The wavelength of middle C note used when playing or singing music, $\lambda=131.87\ cm=1.3187\ m$

We need to find the speed of sound for middle C. We know that the relation between speed, frequency and wavelength is given by the formula as follows :

$v=f\lambda\\\\v=261.63\ Hz\times 1.3187\ m\\\\v=345.01\ m/s$

So, the speed of sound for middle C is 345.01 m/s. Hence, this is the required solution.

8 0

3 years ago

A 2kg block is sitting on a hinged ramp such that you can increase the angle of the incline. The coefficient of static friction

MariettaO [177]

Answer:

θ = 33.8

a = 3.42 m/s²

Explanation:

given data

mass m = 2 kg

coefficient of static friction μs = 0.67

coefficient of kinetic friction μk = 0.25

solution

when block start slide

N = mg cosθ .............1

fs = mg sinθ ...............2

now we divide equation 2 by equation 1 we get

$\frsc{fs}{N} = \frac{sin \theta }{cos \theta }$

$\frac{\mu s N }{N}$ = tanθ

put here value we get

tan θ = 0.67

θ = 33.8

and

when block will slide then we apply newton 2nd law

mg sinθ - fk = ma ...............3

here fk = μk N = μk mg cosθ

so from equation 3 we get

mg sinθ - μk mg cosθ = ma

so a will be

a = (sinθ - μk cosθ)g

put here value and we get

a = (sin33.8 - 0.25 cos33.8) 9.8

a = 3.42 m/s²

7 0

2 years ago

What is the resulting direction of a surface wave?

yulyashka [42]

D: Parallel is the resulting direction of a surface wave!

7 0

3 years ago

Read 2 more answers

PLEASE HELPP!!!

LiRa [457]

Answer:

a) The initial momentum of the ball is 22.5 kg·m/s

b) The magnitude of the momentum imparted by the ball is 30 kg·m/s

Explanation:

The question is based on change in momentum

The mass of the ball, m = 0.75 kg

The velocity with which the ball is thrown against the wall, u = 30 m/s

The time duration it takes while the ball is in contact with the wall, Δt = 0.05 sec

The velocity of the ball as it bounce back, v = -10 m/s (The ball moves in the opposite direction)

a) The initial momentum of the ball, $P_{Initial}$ = m × u = 0.75 kg × 30 m/s = 22.5 kg·m/s

b) The final momentum of the ball, $P_{Final}$ = m × v = 0.75 kg × (-10 m/s) = -7.5 kg·m/s

The momentum imparted by the ball, ΔP = The final momentum - The initial momentum

∴ ΔP = $P_{Final}$ - $P_{Initial}$ = -7.5 kg·m/s - 22.5 kg·m/s = -30 kg·m/s

The magnitude of the momentum imparted by the ball, $\left | \Delta P \right |$ = 30 kg·m/s

5 0

2 years ago