Answer:
1.4s
Explanation:
Given parameters:
Mass of ball = 2kg
Force = 8N
Time = 0.35s
Unknown:
Change in velocity = ?
Solution:
To solve this problem, we use the expression obtained from Newton's second law of motion which is shown below:
Ft = m(v - u)
So;
Ft = m Δv
F is the force
t is the time
m is the mass
Δv is the change in velocity
8 x 0.35 = 2 x Δv
Δv = 1.4s
The speed of an object is measured by calculating the distance it travels per unit time.
The formula in Physics for calculating speed is = distance/ time.
Since an object at rest is not covering any distance, the speed is always assumed to be 0 m/s.
Answer:
Explanation:
There are several differences between a physical and chemical change in matter or substances. A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
Answer:
A) 1000 joules
Explanation:
In general work is given by the equation:
(1)
A) With
the displacement and
the force applied, because the force and the displacement are parallel (the crate is pushed horizontally)
is simply
, and because the path is a straight line and the force is constant work is:
(2),

B) The work-energy theorem says that the total work on a body is equal to the change on kinetic energy:
(3)
The total work on the crate is the work done by the push and plus the work of the friction
(4) , as (A) because forces are parallel to the displacement
(5) and
(6), the due friction always has negative sign because is opposite to the displacement, using (6), (5) and (4) on (3):
(3)
C) The energy is lost by friction, so the amount of energy turned into heat is the work the friction does:
(3)