Answer:
A.compared
Explanation:
Fossils help figure out the time that organisms lived. If you know one of the fossils, it can be used as a reference for others around.
Sponges have appendages jointed
You cant skip nothing. All the lessons are important! Sorry about you free time :/
Answer:
a = - 1.987 × 10⁶ ft/s²
t = 6.84 × 10⁻⁴ s
Explanation:
v₀ = 910 ft/s
x = 5 in.
relation v = v₀ - k x
v = 0 as body comes to rest
0 = 900 - 5k/12
k = 2184 s⁻¹
acceleration

where
(A) a = -k × v
at v= 910 ft/s
a = - 1.987 × 10⁶ ft/s²
(B) at x = 3.9 in.
v = 910 - 3.9(2184)/12
v = 200.2 m/s




t = 6.84 × 10⁻⁴ s
Answer:
Approximately
, assuming friction between the vehicle and the ground is negligible.
Explanation:
Let
denote the mass of the vehicle. Let
denote the initial velocity of the vehicle. Let
denote the spring constant (needs to be found.) Let
denote the maximum displacement of the spring.
Convert velocity of the vehicle to standard units (meters per second):
.
Initial kinetic energy (
) of the vehicle:
.
When the vehicle is brought to a rest, the elastic potential energy (
) stored in the spring would be:
.
By the conservation of energy, if the friction between the vehicle and the ground is negligible, the initial
of the vehicle should be equal to the
of the vehicle. In other words:
.
Rearrange this equation to find an expression for
, the spring constant:
.
Substitute in the given values
,
, and
:
