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STALIN [3.7K]
3 years ago
14

A football player throws and accelerates a ball (m = 0.150 kg) from rest to a velocity of 50 m/s in 0.0121 sec. Determine the ac

celeration of the ball first (this is not the answer) and then the force applied by the player's arm to the ball (enter this value). Neglect resistance forces.
Physics
1 answer:
Rasek [7]3 years ago
5 0

Answer:

Acceleration=4m/s²

Force applied =619.8N

Explanation:

Using equation of motion

V=u+at we have: u=o, v=50m/s

50= 0 + a×0.0121

a = 50/0.0121

a= 4m/s²

Neglecting resistance forces

F= ma, where a = v-u/t

F=m×(v-u)/t

F= 0.150 ×(50-0)/0.0121

F=7.5/0.0121

F= 619.8N

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Ethanethiol (; also called ethyl mercaptan) is commonly added to natural gas to provide the ""rotten egg"" smell of a gas leak.
Tju [1.3M]

Answer:

S = 27500J / 308.15molK

Explanation:

Entropy measures the degree of disorganization of a system. It is measured in the entropy change that is equal to the heat exchanged divided by the temperature at which the process occurs.

S2-S1 = Q / T

S = entropy

Q = heat = 27.5 kJ / mol * 1000J / 1KJ = 27500J / mol

T = temperature = 35 + 273.15 = 308.15K

units = J / molK

S = 27500J / 308.15molK

3 0
3 years ago
A car traveling at 60km/h undergoes uniform acceleration at a rate of 2/ms^2 until is velocity reached 120km/h determine the dis
jenyasd209 [6]

Explanation:

Given that,

Initial speed of a car, u = 60 km/h = 16.67 m/s

Acceleration, a = 2m/s²

Final speed, v = 120 km/h = 33.33 m/s

We need to find the distance traveled and the time taken to make the distance.

acceleration = rate of change of velocity

a=\dfrac{v-u}{t}\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{33.33 -16.67 }{2}\\\\t=8.33\ s

let the distance be d.

d=\dfrac{v^2-u^2}{2a}\\\\d=\frac{33.33^{2}-16.67^{2}}{2(2)}\\\\d=208.25\ m

Hence, the distance traveled and the time taken to make the distance is 208.25 m and 8.33 seconds respectively.

3 0
3 years ago
A gang of robbers is escaping across city roofs at night. They come to the edge of one building and need to drop down to their g
REY [17]

Answer:

a) They will hit the ground with a speed of 19.6 m/s.

b) They are at a height of 20 m.

c) It is not a safe jump.

Explanation:

Hi there!

a) The equations of height and velocity in function of time of a free falling body are the following:

h = h0 + v0 · t + 1/2 · g · t²

v = v0 + g · t

Where:

h = height of the object at time t.

h0 = initial height.

v0 = initial velocity.

t = time.

g = acceleration due to gravity (-9.8 m/s² considering downward as negative direction).

v = velocity of the object at time t.

Using the equation of velocity, let's find the velocity at which they will hit the ground. The pebble is dropped (initial velocity = 0) and it takes 2 s to reach the ground:

v = v0 + g · t     (v0 = 0)

v = g · t

v = -9.8 m/s² · 2.0 s

v = -19.6 m/s

They will hit the ground with a speed of 19.6 m/s.

b)Now, we have to use the equation of height:

h = h0 + v0 · t + 1/2 · g · t²

If we place the origin of the frame of reference on the ground, we have to find the initial height (h0) knowing that at t = 2.0 s, h = 0 m

0 m = h0 - 1/2 · 9.8 m/s² · (2.0 s)²

h0 = 1/2 · 9.8 m/s² · (2.0 s)²

h0 = 20 m

They are at a height of 20 m.

c)According to a NASA paper (Issues on Human Acceleration Tolerance After Long-Duration Space Flights, figure 10), if you fall with a vertical velocity greater than 17 m/s it is unlikely that you will survive. So, it is not a safe jump.  

3 0
3 years ago
A clock radio is rated as 30 w of power output. if the radio also draws 30 w at 120 v, which will the current draw be?
g100num [7]
P = IV

I = P/V =  30 / 120 = 0.25 A.

Current = 0.25A  
4 0
3 years ago
A 180 lb crate is on the ground, and a strong rope is attached. You need to move it across the basement floor, which has a coeff
jekas [21]

Answer:

F = 505.13 N

Yes it is better to pull the rope rather than push it

Explanation:

Let the force is applied at an angle of 60 degree

so we will have net vertical force on the crate is given as

F_n + Fsin60 = mg

here we know

m = 180 lb

m = 81.65 kg

F_n = 81.65(9.81) - Fsin60

F_n = 801 - 0.866 F

now friction force on the crate is given as

F_x = \mu F_n

Fcos60 = 0.7(801 - 0.866 F)

0.5F + 0.61F = 560.7

F = 505.13 N

Yes it is better to pull the rope rather than push it

6 0
3 years ago
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