If acceleration is negative does that mean it is slowing down or different direction

A concrete highway is built of slabs 12 m long (20°C). How wide should the expansion cracks between the slabs be (at 20°C) to prevent buckling if the range of temperature is - 30° to + 50°C? (12 x 10⁻⁶ °C⁻¹ for concrete)

As speed increases, how does the potential, kinetic, and total energy levels change?

Having established that a sound wave corresponds to pressure fluctuations in the medium. True or False

Is a nucleus that absorbs at 4.13 δ more shielded or less shielded than a nucleus that absorbs at 11.45 δ?

How can operators avoid damaging Submersed Aquatic Vegetation (SAV) beds that are usually found in shallow areas of water?

The first law of thermodynamics states that ΔE = Q - W. Is this also a statement of the principle of conservation of energy? Yes, the heat added and the change in internal energy of the gas equal the work done by the piston.

How can we calculate the density of a sustance that has irregular volume

A two stage rocket leaves its launch pad moving vertically with an average acceleration of 4 m/s2. at 10 s after launch the first stage of the rocket (now without fuel) is released.

A liquid filled sealed system has cylinders with movable pistons on each end. The face of one piston has an area of 5 cm². The other piston has an area of 500 cm² and is supporting a weight of 2 kN on it.

A turntable is spinning on a frictionless axle when a ball of putty is dropped onto it from above. The putty sticks to the turntable when it lands. Is angular momentum conserved for the turntable and putty (the system) during this process?