A - 0.8d
multiply the item (d) times 80% (which shows a 20% discount since 100%-20%=80%). Convert 80% to a decimal = .8
therefore, 0.8d
Answer:
75 Newtons.
Explanation:
From Newton's second law of motion,
F = m(v-u)/t................... Equation 1
Where F = force exerted by the ball on the bat, m = mass of the ball, v = final velocity of the ball, u = initial velocity of the ball, t = time
Given: m = 0.6 kilogram, u = 0 meter per seconds (at rest), v = 25 meters per seconds, t = 0.2 seconds.
Substitute into equation 1
F = 0.6(25-0)/0.2
F = 3(25)
F = 75 Newton.
Hence the magnitude of the average force exerted by the ball on the bat = 75 Newtons.
Keep the doors closed and make sure there isnt lots of open space between the door and the frame
Answer:
(a) a= 0.139 m/s²
(b) d= 4.45 m
(c) vf= 1.1 m/s
Explanation:
a) We apply Newton's second law:
∑F = m*a Formula (1)
∑F : algebraic sum of the forces in Newton (N)
m : mass (kg)
a : acceleration (m/s²)
Data
F₁= +2.05 * 10³ N : forward push by a motor
F₂= -1.87* 10³ N : resistive force due to the water.
m= 1300 kg
Calculation of the acceleration of the boat
We replace data in the formula (1):
∑F = m*a
F₁+F₂= m*a


a= 0.139 m/s²
b) Kinematics of the boat
Because the boat moves with uniformly accelerated movement we apply the following formulas:
d= v₀t+ (1/2)*a*t² Formula (2)
vf= v₀+at Formula (3)
Where:
d:displacement in meters (m)
t : time interval (s)
v₀: initial speed (m/s)
vf: final speed (m/s)
a: acceleration (m/s²
)
Data
v₀ = 0
a= 0.139 m/s²
t = 8 s
Calculation of the distance traveled by the boat in 8 s
We replace data in the formula (2)
d= v₀t+ (1/2)*a*t²
d= 0+ (1/2)*(0.139)*(8)²
d= 4.45 m
c) Calculation of the speed of the boat in 8 s
We replace data in the formula (3):
vf= v₀+at
vf= 0+( 0.139)*(8)
vf= 1.1 m/s
Answer:
20000 pounds
Explanation:
Generally 1 gallon of fuel burnt gives of 20 pounds of CO₂
Difference in the gallons of fuel burnt

The 20 mpg car burns 1000 gallons of fuel more than the 30 mpg car
The amount of CO₂ would be

The fewer pounds that the 30 mpg car would release is 20000 pounds