I can confirm, your answer is 800J (Or 800 Joules)!
I just took the test and this was the correct answer :)
Answer:
Explanation:
1 ) Let the initial horizontal velocity of car be v .
For vertical displacement
vertical displacement h = 21.3 - 2.3 = 19 m
Time taken to fall by 19 m be t
19 = 1/2 x 9.8 t² ( initial downward velocity is zero )
t = 1.97 s
This is also the time taken to cover horizontal displacement of 54 m which is width of river .
horizontal speed v = 54 / 1.97 m /s
v = 27.41 m /s
2 )
At the time of landing on other side , car will have both vertical and horizontal speed .
vertical speed
v = u + gt
= 0 + 9.8 x 1.97 = 19.31 m /s
horizontal speed will remain same as the initial speed = 27.41 m /s
Resultant speed = √ ( 27.41² + 19.31² )
= √ ( 751.3 + 372.87)
= 33.52 m /s
Answer:The cannons total flight time is 2.23seconds
Explanation:
A ball fired diagonally is fired at an angle of 45° to the horizontal. The motion of the fired ball is a projectile motion. A projectile is a motion in which an object fired into space with an initial velocity U is allowed to fall freely under the influence of gravitational force.
To total time of flight T of the cannon ball can be expressed as;
T = 2Usin(theta)/g where;
U is the initial velocity or speed of the ball = 31m/s
theta is the angle that the ball make with the horizontal = 45°
g is the acceleration due to gravity = 9.81m/s²
Substituting the given datas into the formula we have;
T = 31sin45°/9.81
T = 31×0.7071/9.81
T = 21.92/9.81
T = 2.23seconds