Answer:
a) a = - 0.0833 m / s², b) t = 4.4 s
Explanation:
a) this is a kinematics exercise where the acceleration is along the inclined plane
v = v₀ - a t
a = v₀ - v / t
a = 3 - 8/60
a = - 0.0833 m / s²
b) in this case the final velocity is zero
v = v₀ - a t
0 = v₀ - at
t = v₀ / a
t = 28 / 6.4
t = 4.375 s
t = 4.4 s
Because when an object is in motion it has kinetic energy
Answer:
★The second law of refraction
The ratio of sine of angle of incidence to the sine of angle of refraction is a constant for a light of given colour and for a given pair of media. This law is also called Snell's law of refraction. If 'i' is the angle of incidence and 'r' is the angle of refraction then, Sin i/Sin r = constant
This constant value is called the refractive index of the second medium with respect to the first.
Net force
As it's negative the box will move left
Answer:
25J
Explanation:
Given parameters:
Mass of the dog = 10kg
Speed of the dog = 5m/s
Unknown:
The minimum energy required to stop the dog = ?
Solution:
The dog is moving with a kinetic energy and to stop the dog, an equal amount of kinetic energy generated must be applied to the dog.
To find the kinetic energy;
K.E = 
m v²
m is the mass
v is the velocity
Now insert the parameters and solve;
K.E = x 10 x 5 = 25J
