Answer: - 7500N
Explanation:
Given the following :
Initial Velocity of car = 108km/hr
Time taken to stop after applying brakes = 4s
Mass of passengers in car = 1000kg
Force exerted by the brakes on the car =?
After 4s, then final Velocity (V) = 0
Initial Velocity (u) of the car = 108km/hr
108km/hr = (108 × 1000)m ÷ (3600)s = 30m/s
Force exerted = mass(m) × acceleration(a)
Acceleration of car = Change in Velocity with time
a = (v - u) / t
a = (0 - 30) / 4
a = - 30/ 4
a = - 7.5m/s^2
Therefore,
Force exerted = mass(m) × acceleration(a)
Force exerted = 1000kg × (-7.5)m/s^2
Force exerted = - 7500N
Answer:
0.2 J
Explanation:
The pendulum forms a right triangle, with hypotenuse of 50 cm and base of 30 cm. The height of this triangle can be found with Pythagorean theorem:
c² = a² + b²
(50 cm)² = a² + (30 cm)²
a = 40 cm
The height of the triangle is 40 cm. The height of the pendulum when it is at the bottom is 50 cm. So the end of the pendulum is lifted by 10 cm. Assuming the mass is concentrated at the end of the pendulum, the potential energy is:
PE = mgh
PE = (0.200 kg) (9.8 N/kg) (0.10 m)
PE = 0.196 J
Rounding to one significant figure, the potential energy is 0.2 J.
Answer:
(d) 9 × 10^{3] J
Explanation:
from the question we are given the following:
weight of the man = 6.0 × 10 ^ {2} N
average speed (v) = 3 m/s
time (t) = 3 s
potential energy (U) = ?
We can calculate the increase in potential energy of the man by applying the formula below
increase in potential energy = P₂ - P₁
where
- P₁ is the initial potential energy
- P₂ is the final potential energy
- Potential energy = mass x acceleration due to gravity x height
From physic we know that weight = mass x acceleration due to gravity
- We should take note that the distance in this case is also our height, and we can get it from the formula distance = velocity x time
- Distance = 3 x 5 = 15 meters
- Initial potential energy P₁ is zero because the person was initially in motion and potential energy is the energy at rest.
therefore
potential energy = 6.0 × 10 ^ {2} × 15 = 9 × 10^{3] J
Answer:
I think C
Explanation:
If im right give brainliest :)
