Answer:
It takes 
to accelerate the object from rest to the speed v.
Explanation:
From Newton's second law:
(1)
and the definition of acceleration,
(2)
we can solve this problem. Putting (2) in (1) we have:
and solving for 
and considering the initial time as zero (
) and the initial velocity also zero (
) we have:
Now, for a mass 
and the 
we can wrtie the same equation:
and substituting 
and 
:
So now, it only takes half the time to accelerate the object from rest to the speed v
Answer:
A. The bullet with 0.006kg has more energy
B. When the mass is doubled the kinetic energy increases
Explanation:
Kinetic energy increases when mass increases
kinetic energy increases when velocity increases
Ok, assuming "mj" in the question is Megajoules MJ) you need a total amount of rotational kinetic energy in the fly wheel at the beginning of the trip that equals
(2.4e6 J/km)x(300 km)=7.2e8 J
The expression for rotational kinetic energy is
E = (1/2)Iω²
where I is the moment of inertia of the fly wheel and ω is the angular velocity.
So this comes down to finding the value of I that gives the required energy. We know the mass is 101kg. The formula for a solid cylinder's moment of inertia is
I = (1/2)mR²
We want (1/2)Iω² = 7.2e8 J and we know ω is limited to 470 revs/sec. However, ω must be in radians per second so multiply it by 2π to get
ω = 2953.1 rad/s
Now let's use this to solve the energy equation, E = (1/2)Iω², for I:
I = 2(7.2e8 J)/(2953.1 rad/s)² = 165.12 kg·m²
Now find the radius R,
165.12 kg·m² = (1/2)(101)R²,
√(2·165/101) = 1.807m
R = 1.807m
Answer:
Answer for the question is given in the attachment.
Explanation:
Answer:
Magnitude of fourth displacement is approximately 95 metres,
Direction of fourth displacement is straight west.
