Answer:
Neglecting air resistance, the only force acting on a projectile is gravity.
This force causes the object to accelerate.
Explanation:
As a projectile moves upward, there is a downward force and a downward acceleration due to force of gravity. That is, as the object is moving upward, force of gravity acting on the projectile is causing a steady slowing down of the projectile.
Hence, Gravity is the downward force upon a projectile that influences its vertical motion and causes the parabolic trajectory that is characteristic of projectiles.
From Newton's law of motion, it suggest that force is required to cause an acceleration and not motion. Therefore, force of gravity causes the object to accelerate downwards.
We know that the electric field is equal to 1 E 6 V/m
The distance between the thundercloud and the ground is 1.6km = 1600m
Electric field = Voltage/distance
This means that the breakdown voltage must be equal to
V = 1 E 6 V/m * 1600m = 1.6 E 9 V = 1.6 GV
You can eliminate the answer A because the moon is super cold
For answer B, atmosphere is contained of gasses, not just oxygen alone
Definitely not C
The answer is D because the moon's gravity isn't strong enough to hold the gasses, as a result, only a small amount of gasses has an attraction to it ( the moon has a little atmosphere though) but not enough to be considered
Answer: The elevator must be accelerating.
Explanation:
As the tension force is opposing to the the force of gravity on the load which is hung vertically, and the tension force can adopt any value in order to comply with Newton's 2nd law, if the tension force is less than the force due to gravity, this means that all system is not in equilibrium, so it must be accelerating.
If we assume that the downward is the positive direction, we can write:
mg - T = ma
If T = 0.9 mg, ⇒ mg (1-0.9) =0.1 mg = m a ⇒a = 0.1 g , in downward direction.
