Average speed = (total distance) / (time to cover the distance)
We know:
Average speed = 65 km/hr
Total distance = 1,000 km
Time to cover it = (Driving Time) + 4 hours.
so we can write:
65 km/hr = (1,000 km) / (Driving Time + 4hr)
(I'm going to start calling the driving time 'DT'.
Notice that DT is a number with the units of 'hours'.)
Multiply each side by (DT + 4hr)
(65 km/hr) (DT + 4hr) = 1,000 km
Eliminate parentheses on the left side:
(65·DT km + 260 km) = 1,000 km
Subtract 260km from each side:
65·DT km = 740 km
Divide each side by 65 :
DT = 11.38 hours .
DT (Driving Time) is the time you spent actually driving.
You had to cover the complete 1,000 km in that time.
So while you were driving, you had to do it at a speed of
1,000 km / 11.38 hrs = 87.8 km/hr .
__________________________________________
As long as we're already totally bored by this question,
let's work on it some more, and check my answer:
... Driving for 11.38 hours at a speed of 87.8 km/hr, you cover
(11.38 hr) x (87.8 km/hr) = 999.164 km (close enough to 1,000) .
So far, so good. The distance is taken care of.
With the 4-hour stop, the total trip takes 4 more hours = 15.38 hours.
So the average speed is
(1,000 km) / (15.38 hr) = 65.02 km/hr
Close enough to 65 km/hr. yay !
Answer:
amplitude is commonly for transmitting messages with a radio carrier wave, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal. at the receiving end, the message signal is extracted from the modulated carrier by demodulation. frequency is the encoding of information in a carrier wave with instantaneous frequency. with digital data, the frequency of the carrier is shifted among a set of frequencies, using digits like 1 and 0
<span>Objects X and Y are in a strong magnetic field.
Both objects are removed from the magnetic field, after which
the magnetic domains in Object X remain unchanged while the
domains in Object Y go from being aligned to becoming random.
Object X is a permanent magnet because it retains the alignment
of the domains, while object Y is a temporary magnet because the
domains became random. (B)</span>
Answer:
Explanation:
Digestion is the breaking down of food in order to release energy for the body. The body obtains its required nutrients through the process of digestion. In digestion, food is broken down and energy is released.
Mechanical digestion involves the breakage of food into tiny bits. Chemical digestion uses chemicals secreted in the body to completely and finally breakdown food.
Mechanical digestion helps the course of chemical digestion. In mechanical digestion, food is broken down by chewing, cudding, churning e.t.c. Here large chunks of food are broken down into tiny bits. The tiny fragments of food has more surface area than the bulk mass. Increase in surface area makes chemical reactions on food very fast. As the food is being subjected to mechanical breakage, chemical action takes place simultaneously.
The food being broken would then be mixed with chemical substances in the body for proper breakage. Chemical digestion completes the digestive process. Chemically digested food can easily be taken into the blood stream where they are transported to different sites within the body.
