Answer:
-30m/s
Explanation:
Given:
Initial velocity of object = 200 feet/second
Final velocity of object = 50 feet/second
Time of travel = 5 seconds
To calculate acceleration of the object we will find the rate of change of velocity with respect to time.
So, acceleration "a" is given by:
where vf represents final velocity, vi represents initial velocity and is time of travel.
Plugging in values to evaluate acceleration.
The acceleration of the object is -30m/s
Answer:
The potential energy of the hiker is 
.
Explanation:
Given that,
Mass of the hiker, m = 61 kg
Height above sea level, h = 1900 m
We need to find the potential energy associated with a 61-kg hiker atop New Hampshire's Mount Washington. The potential energy is given by :
g is the acceleration due to gravity
So, the potential energy of the hiker is . Hence, this is the required solution.
- The mechanic did 5406 Joules of work pushing the car.
That's the energy he put into the car. When he stops pushing, all the energy he put into the car is now the car's kinetic energy.
- Kinetic energy = (1/2) (mass) (speed²)
And there we have it
- The car's mass is 3,600 kg.
- Its speed is 'v' m/s .
- (1/2) (mass) (v²) = 5,406 Joules
(1/2) (3600 kg) (v²) = 5406 joules
1800 kg (v²) = 5406 joules
v² = (5406 joules) / (1800 kg)
v² = (5406/1800) (joules/kg)
= = = = = This section is just to work out the units of the answer:
- v² = (5406/1800) (Newton-meter/kg)
- v² = (5406/1800) (kg-m²/s² / kg)
= = = = =
v = √(5406/1800) m/s
<em>v = 1.733 m/s</em>
Answer:
30 hours
15 hours.
Explanation:
Let the Kelly used sprinkler for t hours and Gracia used the sprinkler for the rest ie (45 - t) hours .
Water output by Kelly = (35 x t) L
Water output by Gracia = 20 ( 45 - t ) L
Total output = 35t + 20(45 - t)
So, 35 t + 20 (45 - t ) = 1350
35 t + 900 - 20 t = 1350
15 t = 450
t = 30 hours
So Kelly used sprinkler for 30 hours and Gracia used it for 45 - 30 = 15 hours.
