First, the infinitive phrase must contain the word "to", so the only options are A and D.
In D "to" is a preposition: it specifies the spacial relation: to the grocery store.
The infinitive phrase is "to go" and the answer is A.
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Answer:
t = 300.3 seconds
Explanation:
Given that,
The mass of a freight train, 
Force applied on the tracks, 
Initial speed, u = 0
Final speed, v = 80 km/h = 22.3 m/s
We need to find the time taken by it to increase the speed of the train from rest.
The force acting on it is given by :
F = ma
or

So, the required time is 300.3 seconds.
Answer:1384 Hz
Explanation:
Given
wavelength
=0.25 m
Temperature T
at
velocity of sound is 346 m/s
and we know



f=1384 Hz
Sound travels at approximately 1,100 feet per second (766 miles per hour). Radio waves travel at the speed of light, which is approximately 186,000 miles per second. This means that in the time radio waves travel the length of a football field, light can travel further than all the way around the world.