Answer:
15s
Explanation:
Given parameters:
Distance traveled = 375m
Speed = 25m/s
Unknown:
Time taken = ?
Solution:
To solve this problem, we make time the subject of the speed equation.
Speed =
Time =
Now insert the parameters and solve;
Time = = 15s
Answer:
The shell hit at a distance of 1.9 x 10² km
The time of flight of the shell was 5.3 x 10² s
Explanation:
The position of the shell is given by the vector "r":
r = (x0 + v0 * t * cos α ; y0 + v0 * t * sin α + 1/2 g t²)
where:
x0 = initial horizontal position
v0 = magnitude of the initial velocity
t = time
α = launching angle
y0 = initial vertical position
g = acceleration of gravity
When the shell hit, the vertical component (ry) of the vector position r is 0. See figure.
Then:
ry = 0 = y0 + v0 * t * sin α + 1/2 g t²
Since the gun is at the center of our system of reference, y0 and x0 = 0
0 = t (v0 sin α + 1/2 g t)
t= 0 is discarded as solution
v0 sin α + 1/2 g t = 0
t = -2v0 sin α / g
t = (-2 * 2610 m/s * sin 81.9°)/ (-9.8 m/s²) = 5.3 x 10² s. This is the time of flight of the shell until it hit.
Then, the distance at which the shell hit is:
Distance = Module of r = ( x0 + v0 * t * cos α; 0) = x0 + v0 * t * cos α
Distance = 2.61 km/s * 5.3 x 10² s * cos 81.9 = 1.9 x 10² km
The work done against gravity is 100 J
Explanation:
The work done against gravity in order to lift an object is equal to the change in gravitational potential energy of the object:
where
m is the mass of the object
g is the acceleration of gravity
is the change in height of the object
For the object in this problem, we have:
m = 5 kg
Substituting into the equation,
Learn more about work:
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Answer:
Groceries stay in the bag.
Explanation:
Given:
Maximum force = 250 N
Bag filled with = 20 kg
Lifted acceleration =
Solution:
We need to calculate the exerted force on the grocery bag by using Newton's second law.
Where:
F = Exerted force on the object.
m = Mass of the object in kg
a = Acceleration of the object in
Now, we substitute m = 20 kg and a = in Newton's second law,
Since, the exerted force on the bag is less than 250 N, the groceries will stay in the bag.