The universe is 13.8 billion years old.
Answer:
a) 1450watts
b) 564watts
c) 1.11
Explanation:
Power consumed = IV
I is the current rating
V is the operating voltage
If a blow-dryer and a vacuum cleaner each operate with a voltage of 120 V and the current rating of the blow-dryer is 12 A, while that of the vacuum cleaner is 4.7 A then their individual power rating is calculated thus;
a) For blow-dryer
Operating voltage = 120V
Its current rating = 12A
Power consumed = IV
= 120×12
= 1440watts
b) For vacuum cleaner:
Operating voltage is the same as that of blow dryer = 120V
Its current rating = 4.7A
Power consumed = IV
= 120×4.7
= 564watts
c) Energy used = Power consumed × time taken
Energy used = Power × time
Energy used by blow dryer = 1440×20×60
= 1,728,000Joules
Energy used up by vacuum cleaner = 564×46×60
= 564×2760
= 1,556,640Joules
Ratio of the energy used by the blow-dryer in 20 minutes to the energy used by the vacuum cleaner in 46 minutes will be 1,728,000/1,556,640 = 1.11
Answer: 288.8 m
Explanation:
We have the following data:
is the time it takes to the child to reach the bottom of the slope
is the initial velocity (the child started from rest)
is the angle of the slope
is the length of the slope
Now, the Force exerted on the sled along the ramp is:
(1)
Where 
is the mass of the sled and 
its acceleration
In addition, if we draw a free body diagram of this sled, the force along the ramp will be:
(2)
Where 
is the acceleration due gravity
Then:
(3)
Finding :
(4)
(5)
(6)
Now, we will use the following kinematic equations to find :
(7)
(8)
Where 
is the final velocity
Finding from (7):
(9)
(10)
Substituting (10) in (8):
(11)
Finding :
Answer:
58.24 Km/h.
Explanation:
From the question given above, the following data were obtained:
Distance (d) = 495 Km
Time (t) = 8 h 30 mins
Speed (S) =?
Next, we shall express 8 hours 30 mins to hours.
We'll begin by convert 30 mins to hour.
60 mins = 1 h
Therefore,
30 mins = 30 mins × 1 h/ 60 mins
30 mins = 0.5 hour.
Thus,
8 h 30 min = 8 + 0.5 = 8.5 hours
Speed is define as the distance travelled per unit time. Mathematically, it is expressed as:
Speed = Distance /time
With the above formula, we can obtain the speed as shown below:
Distance (d) = 495 Km
Time (t) = 8.5 hour
Speed (S) =?
Speed = Distance /time
Speed = 495 Km / 8.5 hour
Speed = 58.24 Km/h
Thus, the speed is 58.24 Km/h.
Answer:
(a) the blocks all had different masses.
Explanation:
The surface is smooth, therefore coefficient of friction is tending to zero.
Forces for each blocks varied from 6N to 8N to 7N to 5N
The blocks were made of different materials and different materials are going to have varying weight for the same size of block.
