Answer:
Answer:
15.67 seconds
Explanation:
Using first equation of Motion
Final Velocity= Initial Velocity + (Acceleration * Time)
v= u + at
v=3
u=50
a= - 4 (negative acceleration or deceleration)
3= 50 +( -4 * t)
-47/-4 = t
Time = 15.67 seconds
Answer:
11.48 m
Explanation:
initial velocity (u) = 15 m/s
acceleration due to gravity (g) = 9.8 m/s
final velocity (v) = 0 ( the ball's speed reduces gradually when thrown until
becomes 0 at maximum height)
find the height reached.
- height (s) = ut + 0.5 at^{2}
we cannot apply this formula directly because we do no know the time
(t), so we first need to find the time
0 = 15 + (-9.8 x t) (the negative sign is because the ball is decelerating
upwards)
15 = 9.8t
t = 1.53 s
- now that we have the time we can put it into the initial equation
- height (s) = ut + 0.5 at^{2}
height (s) = (15 x 1.53) + (0.5 x (-9.8) x 1.53^{2})
height = 22.95 - 11.47 = 11.48 m
The correct option is this: KINETIC ENERGY JUST BEFORE REACHING THE GROUND IS LESS THAN THE GRAVITATIONAL POTENTIAL ENERGY AT THE TOP OF THE BUILDING.
When the object was on the top of the building, it has potential energy. This potential energy was converted to kinetic energy when the object started falling. In the process of falling, friction was present, which means that some of the energy will be converted to heat as a result of the friction. Therefore the kinetic energy of the falling object will be less than its potential energy, because some of the energy has been spent on friction.<span />
Answer:
The acceleration would be positive, pointing to the right.
Explanation:
The acceleration tells us how velocity changes every second. If the train stops, this means its velocity must go from a non-zero value to zero.
To reduce velocity, acceleration must point to the opposite direction. Since velocity is negative, acceleration must be positive.