Answer:
A. 10 joules
Explanation:
Given parameters:
Mass of object = 4kg
Speed = 5m/s
Unknown:
Kinetic energy of the the object = ?
Solution:
Kinetic energy is the energy due to a moving body.
So;
mathematically;
K.E = 
x m v²
m is the mass
v is the velocity
K.E = x 4 x 5 = 10J
Answer:
Negative
Explanation:
If a negatively charged object is used to charge a neutral object by induction, then the neutral object will acquire a positive charge. And if a positively charged object is used to charge a neutral object by induction, then the neutral object will acquire a negative charge:
We have a neutral sphere
1) Electrons are attracted to the positive charge
2) Electrons enter the sphere from ground, attrated to the + charge in the sphere
3) The sphere has an excess of e- having entered from the ground
4) Electrons redistribute uniformly
1) The grapefruit is in free fall, so it moves by uniformly accelerated motion, with constant acceleration
. Calling h its height at t=0, the height at time t is given by
We are told thatn when
the grapefruit hits the ground, so h(0.75 s)=0. If we substitute these data into the equation, we can find the initial height h of the grapefruit:
2) The speed of the grapefruit at time t is given by
where
is the initial speed of the grapefruit. Substituting t=0.75 s, we find the speed when the grapefruit hits the ground:
