Answer;
C.It is the minimum amount of material needed to sustain a fission reaction.
Explanation;
-A critical mass is the smallest or the minimum amount of fissile material needed for a sustained nuclear chain reaction. A critical mass must be achieved in order for the chain reaction to continue and release the atomic energy. A critical mass is needed for both a nuclear reactor and an atomic or hydrogen bomb.
-The critical mass of a fissionable material depends upon its nuclear properties (specifically, the nuclear fission cross section), its density, its shape, its enrichment, its purity, its temperature, and its surroundings.
Answer:
270 mi/h
Explanation:
Given that,
To the south,
v₁ = 300 mi/h, t₁ = 2 h
We can find distance, d₁

To the north,
v₂ = 250 mi/h, d₂ = 750 miles
We can find time, t₂

Now,
Average speed = total distance/total time

Hence, the average speed for the trip is 270 mi/h.
Answer:
15.6m/s
Completed Question;
For a short period of time, the frictional driving force acting on the wheels of the 2.5-Mg van is N= 600t^2 , where t is in seconds. If the van has a speed of 20 km/h when t = 0, determine its speed when t = 5
Explanation:
Mass m = 2500kg
Speed v1 = 20km/h = 20/3.6 m/s = 5.556 m/s
To determine speed v2;
Using the principle of momentum and impulse;
mv1 + ∫₀⁵ F dt = mv2
gravity? I am not completly sure but this is my best guess
Answer:
15.625m
Explanation:
Using the equation of motion
v² = u²+2as
u and v are the initial and final velocities
a is the acceleration
s is the distance
Get the acceleration
According to Newton's second law;
F = ma
8 = 10a
a = 8/10
a = 0.8m/s²
We are also given
v = 5m/s
u = 0m/s
Substitute into the formula above
v² = u²+2as
5² = 0²+2(0.8)s
25 = 1.6s
s = 25/1.6
s = 15.625m
Hence the dog will cover a distance of 15.625m before coming to rest