(1)The avrg. speed of a runner in a 400 meter race is 8m/s. How long did it take the runner to complete the race?
I got 50s. Is that right?
(2)Which statement about the movement of an object with zero acceleration is true? The object must be at rest. Is that right?
(3) An object travels for 8 seconds with an avrg. speed of 160 m/s. The distance traveled by the object is ... 20m. Is that right?
That's all thank you so much for your time!!
2007-01-01 11:20:34 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Physics
1) yes
2) No. If acceleration is zero than the velocity is constant so if the object is at rest, it remains at rest, but if it is moving, it continues to move with the same velocity.
3) it is 8*160= 1280 m
2007-01-01 11:24:34 · answer #1 · answered by Sahaja Yogi 2 · 0⤊ 0⤋
1: 400m/8m/s= 50s
the meters cancel each other out and the answer is 50s
2: if an object has no acceleration it can still have a constant velocity. If there no acceleration there is no net force but the object can still move
3: distance is in meters so if you do 160m/s X 8s the seconds cancel out and you have 1280 meters
2007-01-01 20:26:20 · answer #2 · answered by Ahmed 1 · 0⤊ 0⤋
1. correct
2. no - an object with 0 acceleration has a constant velocity, which can be zero (at rest) but does not necessarily have to be
3. no. D=V*T, so D=160*8=1280m
2007-01-01 19:25:33 · answer #3 · answered by Anonymous · 0⤊ 0⤋
1) I think it is correct.
2) Why can't an object be moving at constant velocity and not accelerate?
3) 8 sec x 160m/sec = 1280 m
2007-01-01 19:24:36 · answer #4 · answered by CG 6 · 0⤊ 0⤋
(1) Your answer is correct.
(2) Incorrect. The object COULD be at rest, but it doesn't have to be. What it MUST have is a constant velocity.
(3) Incorrect. Velocity = distance / time, so d=vt.
Thus, d = 8s * 160m/s = 1280m.
2007-01-01 19:54:21 · answer #5 · answered by marbledog 6 · 0⤊ 0⤋