Answer:
5.71 m/s ;
20 m/s
Explanation:
Blue car:
At time, t = 0 ; Initial position = 20 m
Final position, = 60m after 4 seconds
The velocity = change in distance / change in time.
Velocity of blue = (60 - 20)m ÷ ((4 + 3) - 0),
Velocity of blue car = 40 / 7
= 5.71 m/s
Red car:
Initial Position = 0 ; final Position = 60
Time taken = 3 seconds
Velocity of Red car = (60 - 0)m ÷ 3
Velocity of Red car = 60 / 3
= 20 m/s
Answer:
B) protons and neutrons.
Explanation:
The protons and neutrons are located in the nucleus of the atom and represent most of the 'mass' of the atom, that's their count that determine the 'mass' of an atom (like 12 for Carbon).
The electrons rotate around the nucleus and have a negligible mass.
Answer:
Gravity
Explanation:
Gravity is a force that pulls the surface of the earth and keeps the planets in orbits around the sun.
Answer:
the direction of rate of change of the momentum is against the motion of the body, that is, downward.
The applied force is also against the direction of motion of the body, downward.
Explanation:
The change in the momentum of a body, if the mass of the body is constant, is given by the following formula:
p: momentum
m: mass
: change in the velocity
The sign of the change in the velocity determines the direction of rate of change. Then you have:
v2: final velocity = 35m/s
v1: initial velocity = 40m/s
Hence, the direction of rate of change of the momentum is against the motion of the body, that is, downward.
The applied force is also against the direction of motion of the body, downward.
Answer:
a) 0.036 J b) 0.036J c) 0.036 d) 1.9m/s e) 0.18 m
Explanation:
Mass of the dart = 0.02kg, the spring was compressed to 6cm
Work needed to compress the spring = 1/2*k*x ^2 where k is the force constant of the spring in N/m, x is the distance it was compressed in m
Work needed to compress the spring = 0.5 * 20* 0.06^2 since 6cm = 6 / 100 = 0.06 m
Work needed to compress the spring = 0.036J
b) the total energy stored in the spring = the work done to compress the spring = 0.036J
c) kinetic energy of the dart as it leaves the the spring = elastic potential energy stored in the spring = the work done in compressing the = 0.036J using the law of conservation of energy; energy is neither created nor destroyed but transformed from one form to another.
d) 1/2mv^2 = 0.036
mv^2 = 0.036*2
v^2 = 0.036*2 / 0.02 = 3.6
v = √3.6 = 1.897 approx 1.9m/s
e) kinetic energy of the dart = work done against gravity to get the body to height h
Work done against gravity = potential energy conserved at height = -mgh g is negative because the motion is upward while gravity acts downward
0.036 = 0.02 * 9.81 * h
0.036 / ( 0.02*9.81) = h
h = 0.18 m
