Answer:
63.57 kg
Explanation:
weight = 140 lbs
Let the mass is m.
1 lbs = 4.45 N
The weight of an object is defined as the force with which our earth attracts the body towards its centre.
Weight is the product of mass of the body and the acceleration due to gravity of that planet.
W = m x g
On earth surface g = 9.8 m/s^2
Now convert lbs in newton
So, 140 lbs = 140 x 4.45 = 623 N
So, m x 9.8 = 623
m = 63.57 kg
Thus, the mass is 63.57 kg.
2) If she wants to be swept a smaller distance downstream, she heads a bit upstream. Suppose she orients her body in the water at an angle of 37° upstream (where 0° means heading straight accross, how far downstream is she swept before reaching the opposite bank?
3) For the conditions, how long does it take for her to reach the opposite bank?
Answer:
1)
2)
3)
Explanation:
Given:
width of river,
speed of stream with respect to the ground,
speed of the swimmer with respect to water,
Now the resultant of the two velocities perpendicular to each other:
Now the angle of the resultant velocity form the vertical:
so,
Now the distance swept downward:
2)
On swimming 37° upstream:
The velocity component of stream cancelled by the swimmer:
Now the net effective speed of stream sweeping the swimmer:
The component of swimmer's velocity heading directly towards the opposite bank:
Now the angle of the resultant velocity of the swimmer from the normal to the stream:
Now the distance swept downstream:
3)
Time taken in crossing the rive in case 1:
Time taken in crossing the rive in case 2:
Answer:
h≅ 58 m
Explanation:
GIVEN:
mass of rocket M= 62,000 kg
fuel consumption rate = 150 kg/s
velocity of exhaust gases v= 6000 m/s
Now thrust = rate of fuel consumption×velocity of exhaust gases
=6000 × 150 = 900000 N
now to need calculate time t = amount of fuel consumed÷ rate
= 744/150= 4.96 sec
applying newton's law
M×a= thrust - Mg
62000 a=900000- 62000×9.8
acceleration a= 4.71 m/s^2
its height after 744 kg of its total fuel load has been consumed
h= 58.012 m
h≅ 58 m
Answer:
v = 14.35 m/s
Explanation:
As we know that crate is placed on rough bed
so here when pickup will take a turn around a circle then in that case the friction force on the crate will provide the necessary centripetal force on the crate
So here we have
here we have
now we know that
here we have
R = 35 m
g = 9.81 m/s/s
now plug in all values in above equation
The range of the marble when fired horizontally from 1.8m above the ground can be calculated using the equations of motion in physics. First, the time of flight is found using the vertical motion and then the range is calculated using the time of flight and the initial velocity determined from the vertical launch. The marble's range is approximately 8.4m.
To solve this problem, we need to make use of the concept of projectile motion in physics. The most crucial part in solving this type of problem is to break the motion into its horizontal and vertical components.
First, we find the time the projectile is in the air using the vertical motion. Ignoring air resistance, the time a projectile is in the air is determined by the initial vertical velocity and the height from which it drops. Here, the height is given as 1.8m and we can use the equation h = 0.5gt^2, where h is the height, g is the acceleration due to gravity (9.8 m/s^2), and t is the time. After calculating, we find that the time the marble is in the air is about 0.6 seconds.
Now, we can use the time to find the horizontal distance traveled by the marble, a.k.a the range. The range is given by R = vt, where v is the horizontal velocity, which is the same as the initial vertical velocity. From the problem, we know the marble reached a height of 9.0m when shot vertically, which we can use to find the initial velocity using the equation v = sqrt(2gh), where g is the acceleration due to gravity (9.8 m/s^2) and h is the height. We find that the initial velocity is about 14 m/s.
So, the range R = vt = 14m/s * 0.6s = 8.4m. Therefore, the marble's range when fired horizontally from 1.8m above the ground is approximately 8.4m.
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Answer:
Explanation:
Given that,
Height at which the metal sheet is submerge
H= 8ft
Fluid Force at the top side with area sheet of 3ft², A = 3ft²
Weight density of water
w = ρg = 62.4 lb/ft³
The fluid pressure can be calculated using
P = ρgh
But we are already give the weight density ρg
Then,
P = w•h
P = 62.4 × 8
P = 499.2 lb/ft²
The force from top side?
We can calculate the force using the formula for pressure
Pressure = Force /area
P = F/A
F = P×A
F = 499.2 × 3
F = 1497.6 lbs
Answer:
1838216 J
Explanation:
95 km/h = 26.39 m/s
40 km/h = 11.11 m/s
Initial kinetic energy
= .5 x 1600 x(26.39)²
= 557145.67 J
Final kinetic energy
= .5 x 1600 x ( 11.11)²
= 98745.68 J
Loss of kinetic energy
= 458400 J
Loss of potential energy
= mg x loss of height
= 1600 x 9.8 x 340 sin 15
= 1379816 J
Sum of Loss of potential energy and Loss of kinetic energy
= 1379816 + 458400
= 1838216 J
This is the work done by the friction . So this is heat generated.
To calculate the thermal energy dissipated from the brakes of a car, use the equation Q = Mgh/10, where Q is the energy transferred to the brakes, M is the mass of the car, g is the acceleration due to gravity, and h is the height of the hill. The temperature change of the brakes can then be calculated using the equation Q = mc∆T, where m is the mass of the brakes and c is its specific heat capacity.
The thermal energy dissipated from the brakes of a car can be calculated by converting the gravitational potential energy lost by the car into internal energy of the brakes. By using the equation Q = Mgh/10, where Q is the energy transferred to the brakes, M is the mass of the car, g is the acceleration due to gravity, and h is the height of the hill, we can calculate the thermal energy dissipated. From there, the temperature change of the brakes can be calculated using the equation Q = mc∆T, where m is the mass of the brakes and c is its specific heat capacity.
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