Answer:189000J
Explanation:KE=1/2mv^2
1/2(420g)(30m/s)^2
=189000J
14. After finishing her homework, Sue climbs up a 5.00 m high flight of stairs to her bedroom
Find the magnitude of Sue's weight
and how much
work Sue does in climbing the stairs if she
has a mass of 50.0 kg? (4.90 x 2 N, 2450J)
Explanation:
Given parameters:
Height = 5m
Mass of Sue = 50kg
Unknown:
Magnitude of Sue's weight = ?
Work done by Sue = ?
Solution:
Weight is the vertical force exerted by a body in the presence of gravity.
Mathematically;
W = mg
m is the mass
g is the acceleration due to gravity = 9.8m/s²
Weight = 50 x 9.8 = 490N
Work done = Force x distance = weight x height
Work done = 490 x 5 = 2450J
The metal wire is stretched so that its cross-section is still circular but its total length is now 10 meters. What is the resistance of the wire after stretching
An automobile which set the world record for acceleration increase speed from rest to 96 km/h in 3.07 seconds what distance traveled by the time the final speed was achieved
Answer:
41.02m
Explanation:
Given parameters:
Initial velocity = 0m/s
Final velocity = 96km/hr
Time taken = 3.07s
Unknown:
Distance traveled by the time the final speed was achieved = ?
Solution:
To solve this problem, we first find the acceleration of the car;
Acceleration = [tex]\frac{v - u }{t}[/tex]
v is the final velocity
u is the initial velocity
t is the time taken
Now convert the the final velocity to m/s;
96km/hr to m/s;
1 km/hr = 0.278m/s
96km/hr = 96 x 0.278 = 26.7m/s
Now;
Acceleration = [tex]\frac{26.7 - 0}{3.07}[/tex] = 8.69m/s²
So;
v² = u² + 2as
v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
26.7² = 0² + 2 x 8.69 x s
712.89 = 17.38s
s = 41.02m
Q2. You push a crate up a ramp with a force of 10 N. Despite your pushing, the crate slides down the ramp 4 m. How much work did you do
Answer:
40 J
Explanation:
From the question given above, the following data were obtained:
Force (F) = 10 N
Distance (s) = 4 m
Workdone (Wd) =?
Work done is simply defined as the product of force and distance moved in the direction of the force. Mathematically, we can express the Workdone as:
Workdone = force × distance
Wd = F × s
With the above formula, we can obtain the workdone as follow:
Force (F) = 10 N
Distance (s) = 4 m
Workdone (Wd) =?
Wd = F × s
Wd = 10 × 4
Wd = 40 J
Thus, 40 J of work was done.
which of the following is not a mechanical form of energy?
a. Nuclear
b. Kinetic
c. Spring potential
d. Gravitational potential
Answer:
The answer is Spring Potential
Explanation:
Because all the others are a mechanical form of energy
1. A 75.0 kg man pushes on a 500,000kg wall for 250s but it does not move. How
much work does he do on the wall?
Answer:
0J
Explanation:
No work is being done on the wall by the man pushing on it.
Given parameters:
Mass of man = 75kg
Mass of wall = 500000kg
Time = 250s
Unknown:
Work done = ?
Solution:
Work done is the force applied on a body that moves it along a particular path.
For work to be done, distance must be move or displacement must occur.
Since the wall is not moving the distance is 0;
Work done = Force x distance
Since distance is 0m, work done is 0J
The work done on the wall by the man is 0 J.
To calculate the amount of work done by the man, we use the formula below.
Formula:
W = (ma)d............. Equation 1Where:
W = Work done on the wall by the manm = mass of the walla = acceleration of the walld = distance.from the question,
Given:
m = 500000 kga = 0 m/s² (not moving)d = 0 m.Substitute these values into equation 1
W = 500000(0)(0)W = 0 J.Hence, the work done on the wall by the man is 0 J.
Learn more about work done here: https://brainly.com/question/8119756