As per the question Bob drops the bag full with feathers from the top of the building.
The mass of the bag(m)= 1.0 lb
Let the air resistance is neglected.As the bag is under free fall ,hence the only force that acts on the bag is the force of gravity which is in vertical downward direction.
Here the acceleration produced on bag due to the free fall will be nothing else except the acceleration due to gravity i.e g =9.8 m/s^2
Here we are asked to calculate the distance travelled by the bag at the instant 1.5 s
Hence time t= 1.5 s
From equation of kinematics we know that -
S=ut + 0.5at^2 [ here S is the distance travelled]
For motion under free fall initial velocity (u)=0.
Hence S= 0×1.5+{0.5×(-9.8)×(1.5)^2}
⇒ -S =0-11.025 m
⇒ S= 11.025 m
=11 m
Here the negative sign is taken only due to the vertical downward motion of the body .we may take is positive depending on our frame of reference .
Hence the correct option is B.
Answer:
V1 =8.1 m/s
Explanation:
height at highest point (h2) = 4.1 m
height at lowest point (h1) = 0.8 m
acceleration due to gravity (g) = 9.8 m/s^{2}
from conservation of energy, the total energy at the lowest point will be the same as the total energy at the highest point. therefore
mgh1 +
= mgh2 + 
where
- speed at highest point = V2
- speed at lowest point = V1
- mass of the girl and swing = m
- at the highest point, the speed is minimum (V1 = 0)
- at the lowest point the speed is maximum (V2 is the maximum speed)
- therefore the equation becomes mgh1 +
= mgh2
m(gh1 +
) = m(gh2)
gh1 +
= gh2
V1 = 
now we can substitute all required values into the equation above.
V1 = 
V1 = 
V1 =8.1 m/s
The problem statement is simply asking us to convert units. We convert from units of ft^3 to units of m^3. To do this, we need a conversion factor. For this case, we use 1 m is equal to 3.28084 ft. We do as follows:
5.0 ft^3 ( 1 m / 3.28084 ft )^3 = 0.1416 m^3
The gravitational potential energy of the brick is 25.6 J
Explanation:
The gravitational potential energy of an object is the energy possessed by the object due to its position in a gravitational field.
Near the surface of a planet, the gravitational potential energy is given by

where
m is the mass of the object
g is the strength of the gravitational field
h is the height of the object relative to the ground
For the brick in this problem, we have:
m = 8 kg is its mass
g = 1.6 N/kg is the strenght of the gravitational field on the moon
h = 2 m is the height above the ground
Substituting, we find:

Learn more about potential energy:
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Answer:
The decelerating force is 
Solution:
As per the question:
Frontal Area, A = 
Speed of the spaceship, v = 
Mass density of dust, 
Now, to calculate the average decelerating force exerted by the particle:
(1)
Volume, 
Thus substituting the value of volume, V in eqn (1):

where
A = Area
v = velocity
t = time
(2)

From Newton's second law of motion:

Thus differentiating w.r.t time 't':

where
= average decelerating force of the particle
Now, substituting suitable values in the above eqn:
