Answer:
v = 54m/s
Explanation:

a = 7m/s²
u = 12m/s
t = 6s
7 = (v-12)/6
v - 12 = 42
v = 54m/s
(Correct me if i am wrong)
Answer:
(a) 
(b)
Explanation:
It is given that,
Force acting on the particle, F = 12 N
Displacement of the particle, 
Magnitude of displacement, 
(a) If the change in the kinetic energy of the particle is +30 J. The work done by the particle is given by :

is the angle between force and the displacement
According to work energy theorem, the charge in kinetic energy of the particle is equal to the work done.
So,



(b) If the change in the kinetic energy of the particle is (-30) J. The work done by the particle is given by :


Hence, this is the required solution.
The distance travelled by the object during the first 4 seconds is 80 m
<h3>Definition of speed </h3>
Speed is defined as the distance travelled per unit time. Mathematically, it can be expressed as:
Speed = distance / time
With the above formula, we can obtain the distance travelled by the object in the first 4 seconds.
<h3>How to determine the distance travelled </h3>
Speed = distance / time
20 = distance / 4
Cross multiply
Distance = 20 × 4
Distance = 80 m
Complete question:
See attached photo
Learn more about speed:
brainly.com/question/680492
Answer:
Explanation:
There are two hypotheses she could test:
A cat's heart rate changes while it is napping.
A cat's heart rate does not change while it is napping.