The person travels 2.93 (it’s a repeating decimal so 2.933333 but round it to whatever it says round it to) feet per second
Answer:
33.14 m/s
Explanation:
The mass of the block is 121g or .121 kg. As the bullet is lodged in the block the total mass is 121+14 = 135 g or 0.135 kg.
The frictional force that makes the block come to a stop is normal force* coefficient of friction = 0.135 * 9.8 * 0.7 = 0.9261 N
As the block comes to rest after sliding for 8.3 meters the energy it was given by the bullet is
0.135 * 9.8 * 0.7 * 8.3
= 7.69 Nm
Now this energy is provided the bullet. So the energy in the bullet was equal to
1/2 * mv² = 0.5 * 14 * v².
0.5 * 0.014 * v^2 = 0.135 * 9.8 * 0.7 * 8.3 = 7.69
=> 0.007 * v² = 7.69
=> v² = 7.69 / 0.007
=> v² = 1098.57
=> v = √1098.57
=> v = 33.14 m/s
Friction, engine thrust, normal reaction and weight, these are the forces acting on motor when it moves in a straight line
Answer:
Explanation:
Given that,
Ship send 1200Hz down in to the water.
Echo is heard after 3secs
f = 1200Hz
t = 3seconds
Using wave equation
V = fλ
In echo, two distance is travelled before echo can be heard, then we have
V = 2λ × f
Making d subject of the formula
λ = V / ( 2 × f)
So,
As frequency is reduced by half, the wavelength is double.
Notice
That the sound will travel the same distance but only the speed and the frequency will change.
So, the sound would travel twice as fast, so it would take half as much time to return
We have to assume that the truck was not moving
before he started pushing it.
After he did 12 J of work pushing it, the truck had
12 J of kinetic energy.
Kinetic energy = (1/2) (mass) (speed²)
12 J = (1/2) (3 kg) (speed²)
Divide each side by 1.5 kg : 12J / 1.5 kg = speed²
1 J = 1 newton-meter (12 kg-m²/sec²) / (1.5 kg) = speed²
= 1 kg-m² / sec²
(12 / 1.5) ( m²/sec²) = speed²
Speed = √(8 m²/s²)
Speed = 2.83 m/s .
We can't say anything about velocity, because we don't know
anything about the direction in which the truck is moving.